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Is San Diego Tap Water Safe to Drink?

Yes! Generally Safe to Drink*

LAST UPDATED: 7:49 pm, August 5, 2022
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Table of Contents

Can You Drink Tap Water in San Diego?

Yes, San Diego's tap water is generally considered safe to drink as San Diego has no active health based violations of the Safe Drinking Water Act (SDWA) that we are aware of. Other factors such as lead piping in a home, or low levels of pollutants on immunocompromised individuals, should also be considered, however. To find more recent info we might have, you can check out our boil water notice page, the city's water provider website, or San Diego's local Twitter account.

According the EPA’s ECHO database, from April 30, 2019 to June 30, 2022, San Diego's water utility, City of San Diego, had 5 non-health-based violations of the Safe Drinking Water Act. For more details on the violations, please see our violation history section below. The last violation for San Diego was resolved on April 30, 2020. This assessment is based on the City of San Diego water system, other water systems in the city may have different results.

While tap water that meets the EPA health guidelines generally won’t make you sick to your stomach, it can still contain regulated and unregulated contaminants present in trace amounts that could potentially cause health issues over the long-run. These trace contaminants may also impact immunocompromised and vulnerable individuals.

The EPA is reviewing if it’s current regulations around pollutant levels in tap water are strict enough, and the health dangers posed by unregulated pollutants, like PFAS.

Water Quality Report for San Diego Tap Water

The most recent publicly available numbers for measured contaminant levels in San Diego tap water are in its 2020 Water Quality Report. As you can see, there are levels which the EPA considers to be acceptable, but being below the maximum allowable level doesn’t necessarily mean the water is healthy.

Lead in tap water, for example, is currently allowed at up to 15ppb by the EPA, but it has set the ideal goal for lead at zero. This highlights how meeting EPA standards doesn’t necessarily mean local tap water is healthy.

EPA regulations continue to change as it evaluates the long term impacts of chemicals and updates drinking water acceptable levels. The rules around arsenic, as well as, lead and copper are currently being re-evaluated.

There are also a number of "emerging" contaminants that are not currently. For example, PFAS (Per- and polyfluoroalkyl substances), for which the EPA has issued a health advisory. PFAS are called "forever chemicals" since they tend not to break down in the environment or the human body and can accumulate over time.

We recommend looking at the contaminants present in San Diego's water quality reports, or getting your home's tap water tested to see if you should be filtering your water.

San Diego Tap Water Safe Drinking Water Act Violation History - Prior 10 Years

Below is a ten year history of violations for the water system named City of San Diego for San Diego in California. For more details please see the "What do these Violations Mean?" section below.

From April 1, 2020 to April 30, 2020, San Diego had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring Violation, more specifically, the violation code was Monitoring, Routine (RTCR) which falls into the Microbials rule code group, and the Total Coliform Rules rule code family for the following contaminant code: Revised Total Coliform Rule.

From March 1, 2020 to March 31, 2020, San Diego had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring Violation, more specifically, the violation code was Monitoring, Routine (RTCR) which falls into the Microbials rule code group, and the Total Coliform Rules rule code family for the following contaminant code: Revised Total Coliform Rule.

From Feb. 1, 2020 to Feb. 29, 2020, San Diego had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring Violation, more specifically, the violation code was Monitoring, Routine (RTCR) which falls into the Microbials rule code group, and the Total Coliform Rules rule code family for the following contaminant code: Revised Total Coliform Rule.

From Jan. 1, 2020 to Jan. 31, 2020, San Diego had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring Violation, more specifically, the violation code was Monitoring, Routine (RTCR) which falls into the Microbials rule code group, and the Total Coliform Rules rule code family for the following contaminant code: Revised Total Coliform Rule.

From Dec. 1, 2019 to Dec. 31, 2019, San Diego had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring Violation, more specifically, the violation code was Monitoring, Routine (RTCR) which falls into the Microbials rule code group, and the Total Coliform Rules rule code family for the following contaminant code: Revised Total Coliform Rule.

From Jan. 1, 2017 to Dec. 31, 2017, San Diego had 2 non-health based Safe Drinking Water Act violations with the violation category being Monitoring and Reporting, more specifically, the violation code was Monitoring, Regular which falls into the Chemicals rule code group, and the Inorganic Chemicals rule code family for the following contaminant codes: Nitrate, Nitrate.

From Jan. 1, 2014 to Dec. 31, 2014, San Diego had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring and Reporting, more specifically, the violation code was Monitoring, Regular which falls into the Chemicals rule code group, and the Inorganic Chemicals rule code family for the following contaminant code: Nitrate.

From Jan. 1, 2014 to Dec. 31, 2016, San Diego had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring and Reporting, more specifically, the violation code was Monitoring, Regular which falls into the Chemicals rule code group, and the Inorganic Chemicals rule code family for the following contaminant code: Nitrite.

From Jan. 1, 2013 to Dec. 31, 2013, San Diego had 1 non-health based Safe Drinking Water Act violation with the violation category being Monitoring and Reporting, more specifically, the violation code was Monitoring, Regular which falls into the Chemicals rule code group, and the Inorganic Chemicals rule code family for the following contaminant code: Nitrate.

Is there Lead in San Diego Water?

Based on the EPA’s ECHO Database, 90% of the samples taken from the San Diego water system, City of San Diego, between sample start date and sample end date, were at or below, 0.0 mg/L of lead in San Diego water. This is 0% of the 0.015 mg/L action level. This means 10% of the samples taken from San Diego contained more lead.

While San Diego water testing may have found 0.0 mg/L of lead in its water, that does not mean your water source has the same amount. The amount of lead in water in a city can vary greatly from neighborhood to neighborhood, or even building to building. Many buildings, particularly older ones, have lead pipes or service lines which can be a source of contamination. To find out if your home has lead, we recommend getting you water tested.

No amount of lead in water is healthy, only less dangerous. As lead accumulates in our bodies over time, even exposure to relatively small amounts can have negative health effects. For more information, please check out our Lead FAQ page.

Are there PFAS in San Diego Tap Water?

Currently, testing tap water for PFAS isn’t mandated on a national level. We do have a list of military bases where there have been suspected or confirmed leaks. There appears to be at least one military base - NAVBASE CORONADO - near San Diego with suspected leaks.

With many potential sources of PFAS in tap water across the US, the best information we currently have about which cities have PFAS in their water is this ewg map, which you can check to see if San Diego has been evaluated for yet.

Our stance is better safe than sorry, and that it makes sense to try to purify the tap water just in case.

San Diego SDWA Violation History Table - Prior 10 Years

Compliance Period Status Health-Based? Category Code Code Rule Code Contaminant Code Rule Group Code Rule Family Code
04/01/2020 - 04/30/2020 Resolved No Monitoring Violation (MON) Monitoring, Routine (RTCR) (3A) Revised Total Coliform Rule (111) Revised Total Coliform Rule (8000) Microbials (100) Total Coliform Rules (110)
03/01/2020 - 03/31/2020 Resolved No Monitoring Violation (MON) Monitoring, Routine (RTCR) (3A) Revised Total Coliform Rule (111) Revised Total Coliform Rule (8000) Microbials (100) Total Coliform Rules (110)
02/01/2020 - 02/29/2020 Resolved No Monitoring Violation (MON) Monitoring, Routine (RTCR) (3A) Revised Total Coliform Rule (111) Revised Total Coliform Rule (8000) Microbials (100) Total Coliform Rules (110)
01/01/2020 - 01/31/2020 Resolved No Monitoring Violation (MON) Monitoring, Routine (RTCR) (3A) Revised Total Coliform Rule (111) Revised Total Coliform Rule (8000) Microbials (100) Total Coliform Rules (110)
12/01/2019 - 12/31/2019 Resolved No Monitoring Violation (MON) Monitoring, Routine (RTCR) (3A) Revised Total Coliform Rule (111) Revised Total Coliform Rule (8000) Microbials (100) Total Coliform Rules (110)
01/01/2017 - 12/31/2017 Resolved No Monitoring and Reporting (MR) Monitoring, Regular (03) Nitrates (331) Nitrate (1040) Chemicals (300) Inorganic Chemicals (330)
01/01/2017 - 12/31/2017 Resolved No Monitoring and Reporting (MR) Monitoring, Regular (03) Nitrates (331) Nitrate (1040) Chemicals (300) Inorganic Chemicals (330)
01/01/2014 - 12/31/2014 Resolved No Monitoring and Reporting (MR) Monitoring, Regular (03) Nitrates (331) Nitrate (1040) Chemicals (300) Inorganic Chemicals (330)
01/01/2014 - 12/31/2016 Resolved No Monitoring and Reporting (MR) Monitoring, Regular (03) Nitrates (331) Nitrite (1041) Chemicals (300) Inorganic Chemicals (330)
01/01/2013 - 12/31/2013 Resolved No Monitoring and Reporting (MR) Monitoring, Regular (03) Nitrates (331) Nitrate (1040) Chemicals (300) Inorganic Chemicals (330)

What do these Violations Mean?

Safe Drinking Water Act Violations categories split into two groups, health based, and non-health based. Generally, health based violations are more serious, though non-health based violations can also be cause for concern.

Health Based Violations

  1. Maximum contaminant levels (MCLs) - maximum allowed contaminant level was exceeded.
  2. Maximum residual disinfectant levels (MRDLs) - maximum allowed disinfectant level was exceeded.
  3. Other violations (Other) - the exact required process to reduce the amounts of contaminants in drinking water was not followed.

Non-Health Based Violations

  1. Monitoring and reporting violations (MR, MON) - failure to conduct the required regular monitoring of drinking water quality, and/or to submit monitoring results on time.
  2. Public notice violations (Other) - failure to immediately alert consumers if there is a serious problem with their drinking water that may pose a risk to public health.
  3. Other violations (Other) - miscellaneous violations, such as failure to issue annual consumer confidence reports or maintain required records.

SDWA Table Key

Field Description
Compliance Period Dates of the compliance period.
Status Current status of the violation.
  • Resolved - The violation has at least one resolving enforcement action. In SDWIS, this indicates that either the system has returned to compliance from the violation, the rule that was violated was no longer applicable, or no further action was needed.
  • Archived - The violation is not Resolved, but is more than five years past its compliance period end date. In keeping with the Enforcement Response Policy, the violation no longer contributes to the public water system's overall compliance status. Unresolved violations are also marked as Archived when a system ceases operations (becomes inactive).
  • Addressed - The violation is not Resolved or Archived, and is addressed by one or more formal enforcement actions.
  • Unaddressed - The violation is not Resolved or Archived, and has not been addressed by formal enforcement.
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Health-Based? Whether the violation is health based.
Category Code
The category of violation that is reported.
  • TT - Treatment Technique Violation
  • MRDL - Maximum Residual Disinfectant Level
  • Other - Other Violation
  • MCL - Maximum Contaminant Level Violation
  • MR - Monitoring and Reporting
  • MON - Monitoring Violation
  • RPT - Reporting Violation
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Code A full description of violation codes can be accessed in the SDWA_REF_CODE_VALUES (CSV) table.
Contaminant Code A code value that represents a contaminant for which a public water system has incurred a violation of a primary drinking water regulation.
Rule Code Code for a National Drinking Water rule.
  • 110 - Total Coliform Rule
  • 121 - Surface Water Treatment Rule
  • 122 - Long Term 1 Enhanced Surface Water Treatment Rule
  • 123 - Long Term 2 Enhanced Surface Water Treatment Rule
  • 130 - Filter Backwash Rule
  • 140 - Ground Water Rule
  • 210 - Stage 1 Disinfectants and Disinfection Byproducts Rule
  • 220 - Stage 2 Disinfectants and Disinfection Byproducts Rule
  • 230 - Total Trihalomethanes
  • 310 - Volatile Organic Chemicals
  • 331 - Nitrates
  • 332 - Arsenic
  • 333 - Inorganic Chemicals
  • 320 - Synthetic Organic Chemicals
  • 340 - Radionuclides
  • 350 - Lead and Copper Rule
  • 410 - Public Notice Rule
  • 420 - Consumer Confidence Rule
  • 430 - Miscellaneous
  • 500 - Not Regulated
  • 111 - Revised Total Coliform Rule
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Rule Group Code Code that uniquely identifies a rule group.
  • 120 - Surface Water Treatment Rules
  • 130 - Filter Backwash Rule
  • 140 - Groundwater Rule
  • 210 - Stage 1 Disinfectants and Disinfection Byproducts Rule
  • 220 - Stage 2 Disinfectants and Disinfection Byproducts Rule
  • 230 - Total Trihalomethanes
  • 310 - Volatile Organic Chemicals
  • 320 - Synthetic Organic Chemicals
  • 330 - Inorganic Chemicals
  • 340 - Radionuclides
  • 350 - Lead and Copper Rule
  • 400 - Other
  • 500 - Not Regulated
  • 110 - Total Coliform Rules
  • 410 - Public Notice Rule
  • 420 - Consumer Confidence Rule
  • 430 - Miscellaneous
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Rule Family Code Code for rule family.
  • 100 - Microbials
  • 200 - Disinfectants and Disinfection Byproducts Rule
  • 300 - Chemicals
  • 400 - Other
  • 500 - Not Regulated
show details

For more clarification please visit the EPA's data dictionary.

San Diego Water - Frequently Asked Questions

HOW DO WE MAKE WATER DRINKABLE?
The City’s Public Utilities Department provides high-quality drinking water by utilizing proven technology, modern facilities and state-certified operators. Water is treated using several processes, with each process providing additional water quality improvements. Using several treatment processes provides multiple barriers for added levels of safety. Our treatment plants employ a combination of time-tested conventional water treatment processes and innovative disinfection strategies. Both Alvarado and Miramar water treatment plants use ozone for primary disinfection, while the Otay Water Treatment Plant uses chlorine dioxide. Conventional water treatment consists of coagulation, flocculation, sedimentation and sand/ multimedia filtration. This cost-effective, proven method of treatment is used throughout the modern world.
HOW TO READ THE TABLES
The tables on the following pages list parameters that DDW requires the City to monitor, which may be associated with primary (health), secondary (aesthetic) or no established standards. These tables summarize monitoring from January through December 2020. The tables list all parameters that were detected at or above DDW’s Detection Limit for Purposes of Reporting (DLR). The map on page 2 of this report can be used to determine the treatment plant or plants that supply water to your residence. Less than 10% of San Diego’s total water use comes from purchased treated water, which is a blend of water treated at the Metropolitan Water District’s Skinner Water Treatment Plant, the San Diego County Water Authority’s Twin Oaks Valley Water Treatment Plant, and the Carlsbad Desalination Plant.
HOW DO I CONTACT SAN DIEGO CUSTOMER SERVICE?
To contact customer service for the San Diego water provider, City of San Diego, please use the information below.
By Phone: 858-292-6436
By Email: jguerreiro@sandiego.gov
By Mail: 2797 Caminito Chollas
SAN DIEGO, CA, 92105
HOW TO PAY BILL FOR CITY OF SAN DIEGO
Already have an account?

Existing customers can login to their City of San Diego account to pay their San Diego water bill by clicking here.

Want to create a new account?

If you want to pay your City of San Diego bill online and haven't made an account yet, you can create an account online. Please click here to create your account to pay your San Diego water bill.

Want to pay without an account?

If you don't want to make an account, or can't remember your account, you can make a one-time payment towards your San Diego water bill without creating an account using a one time payment portal with your account number and credit or debit card. Click here to make a one time payment.

HOW TO START & STOP SAN DIEGO WATER SERVICE
Starting Your Service

Moving to a new house or apartment in San Diego means you will often need to put the water in your name with City of San Diego. In order to put the water in your name, please click the link to the start service form below. Start service requests for water bills typically take two business days.

Start Service Form

Want to create a new account?

Leaving your house or apartment in San Diego means you will likely need to take your name off of the water bill with City of San Diego. In order to take your name off the water bill, please click the link to the stop service form below. Stop service for water bills requests typically take two business days.

Stop Service Form

Is San Diego Tap Water Safe to Drink? Tap water & safety quality

The estimated price of bottled water

$1.69 in USD (1.5-liter)

USER SUBMITTED RATINGS

San Diego tap water
  • Drinking Water Pollution and Inaccessibility 34% Low
  • Water Pollution 52% Moderate
  • Drinking Water Quality and Accessibility 66% High
  • Water Quality 48% Moderate

The above data is comprised of subjective, user submitted opinions about the water quality and pollution in San Diego, measured on a scale from 0% (lowest) to 100% (highest).

Related FAQS

San Diego Water Quality Report (Consumer Confidence Report)

The EPA mandates that towns and cities consistently monitor and test their tap water. They must report their findings in an annual Consumer Confidence Report. Below is the most recent water quality report from San Diego's Water. If you would like to see the original version of the report, please click here.

2020

Annual Drinking Water Quality Report

2 Annual Drinking Water Quality Report 2020

City of San Diego’s Tap Water Supply Meets All State

and Federal Health Standards in 2020

The City of San Diego is committed to providing you with a clean, safe and stable water supply. It’s the priority of every employee of the City’s Public Utilities Department. Those efforts matter. Based on the water quality monitoring data collected in 2020, the City’s tap water met all state and federal drinking water health standards, which are the primary standards for treating and monitoring water. The U.S. Environmental Protection Agency (EPA) and the California Division of Drinking Water mandate all water agencies to produce an annual document educating customers about their drinking water quality for the previous year. This annual Drinking Water Quality Report details the origin of the City’s water supply, what it contains and how it meets health standards.

A Message from the Director

Last year we celebrated the 60th anniversary of the City’s Miramar Reservoir. It was an opportunity to reflect on our past, focus on our current operations and look forward to upcoming projects.

Not only is Miramar Reservoir an important part of our water supply system, but it has become a very popular recreational area for the public. And in the future, Miramar Reservoir will be a key part of the City’s Pure Water system that will provide more than 40% of our drinking water by 2035.

Two major steps forward that were taken in 2020 to begin construction on the Pure Water system included:

  • Construction bids were advertised for the North City Pure Water Facility, Morena Northern Alignment and Tunnels, Morena Pump Station and expansions of the North City Water Reclamation Plant and North City Pure Water Pipeline, and
  • A U.S. EPA loan was refinanced that will save taxpayers $293 million.

2020 was a difficult year for all of us, and 2021 has its challenges as well. But we are proud that we have been able to continue providing great water and wastewater service to the citizens of San Diego during this pandemic. We adapted in numerous ways by having many employees working from home, instituting new safety protocols at our facilities and in the field and providing more assistance to customers online.

In the coming years you’ll see progress as we build the Pure Water system, continue to upgrade our infrastructure, adapt to better assist the public and improve our water supply to make San Diego a more sustainable city.

Sincerely,

Shauna Lorance

Director of Public Utilities

City of San Diego

CONTACT

Public Utilities Emergency Hotline

619-515-3525

General and Billing Information

619-515-3500

 

 

 

customercare@sandiego.gov

Water Quality Lab

619-668-3232

 

 

 

drinkingwaterquality@sandiego.gov

Capital Improvements Projects

619-533-4207

City Reservoirs Recreation

619-465-3474

Pure Water Program

619-533-6638

Storm Water Pollution Prevention

619-235-1000

Water Waste/Recycled Water

619-533-5271

 

 

VISIT

 

 

.......................

sandiego.gov/public-utilities

 

 

 

City of San Diego Public Utilities

San Diego County Water Authority

sdcwa.org

Metropolitan Water District

mwdh2o.com

California Division of Drinking Water

waterboards.ca.gov

U.S. EPA

water.epa.gov/drink

American Water Works Association

awwa.org

Be Water Wise

bewaterwise.com

Pure Water Program

purewatersd.org

Think Blue

thinkblue.org

ENGAGE

Get It Done App

sandiego.gov/get-it-donefacebook.com/CityofSanDiego

Annual Drinking Water Quality Report 2020 3

Water Supply - What’s in Your Water

Before It’s Treated?

The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material and can pick up substances resulting from the presence of animals or from human activity. Contaminants that may be present in source water include:

  • Microbial contaminants, such as viruses and bacteria that may come from sewage treatment plants, septic systems, agricultural livestock operations and wildlife.
  • Inorganic contaminants, such as salts and metals, that can be naturally occurring or result from urban storm water runoff, industrial or domestic wastewater discharges, oil and gas production, mining or farming.
  • Pesticides and herbicides that may come from a variety of sources such as agriculture, urban storm water runoff and residential uses.
  • Organic chemical contaminants, including synthetic and volatile organic chemicals that are byproducts of industrial processes and petroleum production and can also come from gas stations, urban storm water runoff, agricultural application and septic systems.
  • Radioactive contaminants, that can be naturally occurring or be the result of oil and gas production and mining activities.

In order to ensure that tap water is safe to drink, the U.S. Environmental Protection Agency (EPA) and the State Water Resources Control Board (State Board) prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. The U.S. Food and Drug Administration regulations and California law also establish limits for contaminants in bottled water that provide the same protection for public health. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk.

Your water is treated at one of

Treatment Plant Service Areas

three municipal water treatment

 

plants – Alvarado, Miramar and

 

Otay*.Inordertoprovideareliable

 

supply of high-quality drinking

 

water,theCity’sdistributionsystem

 

is interconnected, and the areas

 

served by each treatment plant

 

overlap. If your residence falls in

 

one of the two sections of this map

 

where service areas overlap, your

 

water could come from either of

 

the treatment plants. To gather

 

information about the water

 

quality at your residence, you may

 

need to refer to multiple columns

 

in the data tables contained in

 

this report.

 

Imported Water Sources

 

*A small portion is treated water

Miramar Treatment Plant

supplied by Metropolitan Water

Alvarado Treatment Plant

District’s Skinner Water Treatment

Plant and the San Diego County

Otay Treatment Plant

Water Authority’s Twin Oaks and

 

Carlsbad Desalination water

 

treatment plants.

 

Imported Water Supply and the Impact on Water Quality

The City of San Diego currently imports most of its water supply, the bulk of which is raw (untreated) water purchased from the San Diego County Water Authority. All raw water is treated before entering the City’s drinking water distribution system. Less than 10% of the imported water purchased from the County Water Authority is a blend of treated water from the Metropolitan Water District’s Skinner Water Treatment Plant, the County Water Authority’s Twin Oaks Valley Water Treatment Plant and the Carlsbad Desalination Plant.

Most of the imported water from the County Water Authority is a blend from the Colorado River and State Water Project (see map to the left). Throughout the year, the ratio of water from each source changes. The constituents that make up the City’s source water are influenced by the water source, climate, geology and the land activities that they flow through. The City continually monitors our source water and adjusts its treatment process to ensure that the water is always healthy and safe.

News on Rate

Increases

You will soon receive information in the mail with details about proposed rate increases for water and wastewater services.

For the first time in 10 years, the City of San Diego is planning to increase wastewater rates, by 5%, starting in January 2022. In addition, the City is proposing to pass through regional water cost increases to its customers.

For more information, visit

www.sandiego.gov/rate-increases

4 Annual Drinking Water Quality Report 2020

HIGHLIGHTSOF2020

The City’s Public Utilities Department achieved a number of important milestones last year that included increasing efficiency, improving services and planning for the future.

City Takes Major Strides Forward with Pure Water Program

Important milestones were achieved in 2020 for the advancement of the City’s Pure Water Program. Pure Water is the City’s phased, multi-year program that will

provide more than 40% of San Diego’s water supply locally by the end of 2035. The Pure Water Program will use proven water purification technology to clean recycled water to produce safe, high-quality drinking water. The Program offers a cost-effective investment for San Diego’s water needs and will provide a reliable, sustainable

water supply. Below are some of the major highlights from 2020:

  • Starting in August, the City began seeking construction bids for the North City Pure Water Facility as the first of several bids for the Pure Water Program, which is expected to deliver more than 400 new jobs aiding in the regional economic recovery effort.
  • The City refinanced a loan with the U.S. EPA in September that will save an estimated $293 million for taxpayers. The Water Infrastructure Finance and Innovation Act (WIFIA) loan from the EPA is providing funding for up to $614 million of the costs of the Pure Water Program’s Phase I projects.
    Up to about 97% of the Pure Water project costs are expected to be funded with WIFIA loan, State Revolving Fund loans and grant proceeds.
  • The Ocean Pollution Reduction Act II (OPRA II), passed the House of Representatives in November 2020 by an overwhelming vote of 395-4, but the Senate did not take action on the bill before the end of the two-year legislative session. Congressman Scott Peters re-introduced the bipartisan legislation this Congress in January 2021, and the House Transportation & Infrastructure Committee approved it on March 24. OPRA II will be considered by the full House and then will move to the Senate for consideration. Under OPRA II, the City of San Diego must demonstrate that its Pure Water Program can produce 83 million gallons a day of water by 2036. With associated water recycling and conservation efforts, this would reduce treated wastewater flows to the ocean from the Point Loma Wastewater Treatment Plant by over 50%. This reduction in outflow and waste will be continuously monitored and subject to ongoing research efforts by academic, city, state and national entities. This bill ensures that San Diego has long-term certainty for its water supply.

More important steps for the Pure Water Program are anticipated for 2021. More information about the program is available from the City at www.purewatersd.org.

Number of Water Main Breaks Down for Fourth Year in a Row in City of San Diego

For the fourth year in a row, the number of water main breaks decreased in the City of San Diego. There were 33 water main breaks reported in 2020, the lowest

total in more than 15 years and far fewer than the peak of 131 breaks in 2010. The City credits the continued downward trend to increased maintenance efforts and

a multi-year program to replace old pipelines.

The City’s continuing program to replace old cast iron water mains has played a major part in the decrease in breaks. Some cast iron pipes had been in service for more than 100 years. Since 2013, the City has replaced approximately 180 miles of water pipelines across the city. The remaining 55 miles of cast iron water mains are scheduled to be replaced by 2025. The City now uses water mains made of durable polyvinyl chloride (PVC).

Annual Drinking Water Quality Report 2020 5

City of San Diego Marks Major Milestone with Miramar Reservoir’s 60th Anniversary and Vital Role for Region’s Future

In 2020, the City commemorated the 60th anniversary of Miramar Reservoir while planning for the facility’s important role in the City’s future water needs. For the past six decades, Miramar Reservoir has served millions of San Diegans as part of the City’s water system and as a popular recreational area. Now the City plans to use the reservoir as part of its Pure Water Program system.

Miramar was the last of the City’s nine reservoirs to be created. Its construction was completed in 1960 as part of the second San Diego Aqueduct. Imported water is pumped from the aqueduct to the reservoir before it is treated by the adjacent Miramar Water Treatment Plant and delivered to customers.

When the Pure Water Program comes online, Miramar Reservoir will switch from holding imported water to holding purified water that is received through a pipeline from the planned North City Pure Water Facility. The water will then go through a second treatment process at the Miramar Water Treatment Plant before being distributed to homes and businesses.

Since the mid-1960s, the reservoir has been a popular recreational destination. An estimated 100,000 people visit

Miramar each year to enjoy jogging, biking, fishing, boating, picnicking and other activities. More information about

Miramar and other City reservoirs is available at www.sandiego.gov/reservoirs-lakes.

City of San Diego Participated in Statewide Program to Monitor Wastewater for Virus That Causes COVID-19

The City of San Diego participated in a statewide program to monitor its untreated wastewater for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. Public Utilities Department staff collected samples to be analyzed for SARS-CoV-2 in untreated wastewater at the Point Loma Wastewater Treatment Plant once a week in December 2020. Following this test run, staff collected samples to be analyzed for SARS-CoV-2 three times a week from January through June 2021. All data was reported to the state within 24 hours of receiving results.

The California Department of Public Health and the State Water Resources Control Board initiated the Wastewater- based Epidemiology Program in coordination with the Centers for Disease Control and Prevention and are participating in the National Wastewater Surveillance System (NWSS), a collaborative effort among states to monitor wastewater. The NWSS will then inform the incidence, spread and control or epidemiology of COVID-19 to improve public

health decision making. The City’s Public Utilities Department was one of five large agencies in California that was already voluntarily participating in a State Water Resources Control Board sponsored research project with the Water Research Foundation titled “Measure Pathogens in Wastewater” (DPR-2) to generate bi-monthly SARS-CoV-2 data in untreated wastewater.

The City’s participation in DPR-2 is not only important for advancing pathogen monitoring for direct potable reuse projects, but the data can also potentially improve the state’s ability to respond to the current pandemic and plan for future outbreaks.

In addition, the City participated in multiple studies of its wastewater related to COVID-19, including those with San Diego State University, University of Arizona and the Southern California Coastal Water Research Project.

The City’s collection, treatment and disposal of wastewater are carefully monitored and meet all regulations ensuring the health and safety of our employees, community members and the environment.

While SARS-CoV-2’s presence and viability in wastewater is still being examined by the scientific community, the wastewater treatment environment has been shown to be very effective in removing many other viruses and bacteria that are commonly found in the City’s wastewater systems.

For more information about City efforts regarding COVID-19, please visit www.sandiego.gov/coronavirus.

6 Annual Drinking Water Quality Report 2020

How Do We Make Water Drinkable?

WATER TREATMENT

The City’s Public Utilities Department provides high-quality drinking water by utilizing proven technology, modern

facilities and state-certified operators. Water is treated using several processes, with each process providing additional

water quality improvements. Using several treatment processes provides multiple barriers for added levels of safety. Our treatment plants employ a combination of time-tested conventional water treatment processes and innovative

disinfection strategies. Both Alvarado and Miramar water treatment plants use ozone for primary disinfection, while the Otay Water

Treatment Plant uses chlorine dioxide. Conventional water treatment consists of coagulation, flocculation, sedimentation and sand/ multimedia filtration. This cost-effective, proven method of treatment is used throughout the modern world.

STAGES OF OUR WATER TREATMENT

Watershed protection: Protecting the watersheds prevents contamination

of our water supply and is the most cost-effective process in water treatment.

Extensive measures are taken to prevent contamination of our local and imported water. If you see “No Swimming” or “No Dumping” signs posted near water supplies, this is for the protection of your drinking water. The latest Watershed Sanitary Survey, which contains information on the City’s watersheds, including water quality and vulnerabilities, is available at: sandiego.gov/public-utilities/

water-quality/watersheds/sanitary-survey.

Coagulation: This is the chemical process of rapidly mixing coagulants into the water entering the water treatment plant. Many of the particles in the source water have negative charges, causing them to repel each other, much like two magnets when the negative ends are put together. Coagulation changes these negative charges to neutral.

Flocculation: Coagulated water is slowly mixed causing the neutral particles

to collide. When the collisions occur, the particles clump together forming floc. As the floc is formed, particles in the water are trapped within the floc. The floc now looks like snowflakes suspended in the water.

Sedimentation: The floc particles are heavier than water. Mixing is stopped and the water slowly flows through the sedimentation basins, during which the floc settles to the bottom and is removed. The clear water is collected from the

top of the sedimentation basins.

Disinfection, Primary: Drinking water is further treated to remove or inactivate viruses, bacteria and other pathogenic organisms. Disinfection is accomplished in a variety of methods. The Alvarado and Miramar water treatment plants use ozone as the primary disinfectant. The Otay Water Treatment Plant uses chlorine dioxide as the primary disinfectant. These are advanced disinfection processes and have the advantage of providing higher quality water with better taste.

Filtration: Water is passed through deep filtration beds to produce water

that is crystal clear. Extremely small particles are removed during this process. San Diego’s water treatment plants produce water with turbidity (cloudiness)

significantly better than drinking water standards, indicating a highly effective

treatment process and resulting in high-quality drinking water.

Disinfection, Secondary: Chloramines are created by adding chlorine and ammonia to the water. Chloramines help prevent microbial contamination from occurring in the water distribution system.

Corrosion Control: The corrosivity of the water is controlled by adjusting the pH.

Reservoir

Coagulation

Flocculation/

Filtration

Treated

Water

 

 

Sedimentation

 

Storage

Water

Pre-Ozone,

 

Miramar

Primary

Disinfection,

Chlorine Dioxide,

Otay WTP

Ferric Chloride

Polymer

Primary

Disinfection,

Ozone, Alvarado

& Miramar WTP

Anthracite Coal

Silica Sand

Support Media

Chlorine

Ammonia

 

Sodium Hydroxide

 

Fluoride

NOTICE OF VIOLATIONS

Under state law, the City of San Diego is required to collect at least 85 bacteriological water samples per week under the City’s Bacteriological Sample Siting Plan. On April 29, 2020, and May 5, 2020, the City of San Diego discovered that two laboratory technicians had falsified data by collecting multiple samples from single sample sites. Using GPS data collected from City vehicles, it was discovered that a total of 139 routine bacteriological samples were not collected during the months of December 2019 and April 2020 as scheduled in the City’s Bacteriological Sample Siting Plan. A complete incident report was submitted by the City to the state Department of Drinking Water on June 4, 2020. The State Water Board assessed an administrative penalty of $15,000 for the falsification of data.

A CHANGE FOR THE BETTER…

 

 

 

 

 

 

SAN DIEGO

 

 

 

 

THINK BLUE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BEGINS

WITH

YOU.

Did you know that San Diego’s storm water system is separate from its water or wastewater system? Many people think that when water flows into a storm drain it is treated, but the storm drain system and the sewer system are not connected. Everything that enters storm drains flows untreated directly into our creeks, rivers, bays, beaches and ultimately the ocean.

That’s why Think Blue, the City of San Diego’s storm water outreach and education program, wants you to know that you have the power to keep trash, debris, sediments, metals, pesticides and other pollutants out of our storm drains and waterways by taking a few easy steps.

How You Can Help

Our Storm Water System

Sweep Up Around Your Yard: Sweep up dirt, debris and yard waste and dispose of them properly. Yard waste has the potential to carry hazardous landscaping chemicals such as pesticides and fertilizers into the storm drain system and generate large amounts of bacteria if left to decompose in gutters, drains and local waterways.

Eliminate Over-Irrigation: Prevent water from leaving your property so it won’t carry pollutants into our storm drains during dry weather. Sweep hard surfaces instead of hosing them off with water, adjust and maintain sprinklers so they don’t spray onto your driveway or sidewalk and fix leaks promptly.

When It Rains: During the rainy season, redirect rain gutter downspouts to landscaped areas where the water can be absorbed and replenish groundwater or connect your downspout to a rain barrel to store the water for later use.

From Your Car: Your car can be a source of automotive pollutants such as motor oil. It’s important to check your car regularly for fluid leaks.

From Curb to Ocean: The City of San Diego oversees the operation and maintenance of 48,000 storm drain structures, 1,148 miles of pipe and 15 pump stations designed to control flooding by moving rain water away from the public and property to transport it to local waterways.

Aging Infrastructure: Maintenance of our storm water system is partially funded by a small storm water fee included in your water bill and supplemented by other City funds. It’s estimated that almost $900 million are needed in the next five years to fully fund the repairs and improvements required for the maintenance of this infrastructure and protect the quality of our waterways.

Vital to San Diego: A fully functional and operational modern storm water system is important to the environmental and economic health of San Diego and is essential to our quality of life.

Think Blue appreciates everything you do to help protect our local waterways. Visit ThinkBlue.org for more information on how you can prevent pollution in our waterways.

To report storm water pollution in San Diego, call the Think Blue Hotline at 619-235-1000 or report it using the Get It Done App or on your desktop at SanDiego.gov/getitdone.

8 Annual Drinking Water Quality Report 2020

Important Health Information

Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA/Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline (1-800-426-4791).

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health

risk. More information about contaminants and potential health effects can be obtained by calling the EPA

Safe Drinking Water Hotline at 1-800-426-4791. For detailed information on drinking water regulations, visit the California Division of Drinking Water (DDW) website at waterboards.ca.gov/drinking_water.

CRYPTOSPORIDIUM AND GIARDIA

Cryptosporidium and Giardia are microbial contaminants that are naturally present in the environment and found in surface water throughout the United States. Disinfection

and filtration are highly effective in removing these contaminants; however, the disinfection and filtration methods cannot guarantee 100% removal. During calendar year

2020, the water supply to each of the City’s water treatment plants was monitored for Cryptosporidium and Giardia, and neither was detected.

HOW TO READ THE TABLES

The tables on the following pages list parameters that DDW requires the City to monitor, which may be associated with primary (health), secondary (aesthetic) or no established standards. These tables summarize monitoring from January through December 2020. The tables list all parameters that were detected at or above DDW’s Detection Limit for Purposes of Reporting (DLR). The map on page 2 of this report can be used to determine the treatment plant or plants that supply water to your residence. Less than 10% of San Diego’s total water use comes from purchased treated water, which is a blend of water treated at the Metropolitan Water District’s Skinner Water Treatment Plant, the San Diego County Water Authority’s Twin Oaks Valley Water Treatment Plant, and the Carlsbad Desalination Plant.

DEFINITION OF TERMS

Action Level (AL): The concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.

Location-based Running Annual Average (LRAA): The average of the most recent four quarters of monitoring performed at a distinct location in the distribution system. Location-based Running Annual Averages are calculated quarterly using 12 months of data and may include values obtained in 2018.

Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. Primary Maximum Contaminant Levels are set as close to the Public Health Goals or Maximum Contaminant Level Goals as is economically and technologically feasible. Secondary Maximum Contaminant Levels are set to protect the odor, taste and appearance of drinking water.

Maximum Contaminant Level Goal (MCLG): The level of a contaminant in drinking water below which there is no known or expected health risk. Maximum Contaminant Level Goals are set by the U.S. Environmental Protection Agency.

Maximum Residual Disinfectant Level (MRDL): The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

Maximum Residual Disinfectant Level Goal (MRDLG): The level of a drinking water disinfectant below which there is no known or expected risk to health. Maximum Residual Disinfectant Level Goals do not reflect the benefits of the use of disinfectants to control microbial contaminants.

Notification Level (NL): Health-based advisory levels established by the Division of Drinking Water for chemicals in drinking water that lack Maximum Contaminant Levels. When chemicals are found at concentrations greater than their notification levels, certain requirements and recommendations apply.

Public Health Goal (PHG): The level of a contaminant in drinking water that does not pose a significant risk to health. Public Health Goals are not regulatory standards.

Primary Drinking Water Standard (PDWS): Maximum Contaminant Levels, Maximum Residual Disinfection Levels and treatment techniques for contaminants that affect health, along with their monitoring and reporting requirements.

Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.

ABBREVIATIONS

  1. absent

CA SMCL: California Secondary Maximum Contaminant Level

CU: color units

DLR: detection limit for reporting

gr/Gal: grains per gallon

MDL: City of San Diego Water Quality Laboratory Method Detection Limit –

the lowest quantifiable concentration of a measured parameter detectable by the laboratory.

mL: milliliter

n/a: not applicable

ND: not detected (less than DLR, where applicable)

NTU: nephelometric turbidity units

OU: odor units

pCi/L: picocuries per liter (a measure of radiation)

ppb: parts per billion or micrograms per liter (μg/L) – [1 ppb = 0.001 ppm]

ppm: parts per million or milligrams per liter (mg/L) – [1 ppm = 1,000 ppb]

μS/CM: micro-siemens/centimeter

  • less than
  • greater than

Annual Drinking Water Quality Report 2020 9

ENVIRONMENTAL MONITORING AND TECHNICAL SERVICES

CONSUMER CONFIDENCE REPORT DATA - 2020

PRIMARY STANDARDS (MANDATORY HEALTH RELATED STANDARDS)

 

 

 

 

 

 

CITY OF SAN DIEGO TREATMENT PLANTS

 

 

PURCHASED

 

 

 

 

 

 

 

 

 

 

 

 

 

TREATED WATER

 

 

 

 

 

 

ALVARADO

MIRAMAR

 

OTAY

MAJOR SOURCES

 

 

 

 

 

 

 

 

CHEMICAL PARAMETERS

UNITS

MCL

PHG

DLR

AVERAGE

RANGE

AVERAGE

RANGE

AVERAGE

 

RANGE

AVERAGE

RANGE

IN DRINKING WATER

Aluminum

ppm

1

0.6

0.05

ND

ND - ND

ND

ND - ND

ND

 

ND - ND

ND

ND - 0.2

Erosion of natural deposits;

 

residue from some surface water

 

 

 

 

 

 

 

 

 

 

 

 

 

 

treatment processes

Barium

ppm

1

2

0.1

ND

ND - ND

ND

ND - 0.1

ND

 

ND - ND

ND

ND - ND

Erosion of natural deposits;

 

discharges of oil drilling wastes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fluoride (naturally occurring)

ppm

2.0

1

0.1

0.3

0.2 - 0.4

0.2

0.1 - 0.4

0.3

 

0.2 - 0.5

0.4

0.1 - 1.0

Erosion of natural deposits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fluoride (treatment-related)*

ppm

2.0

1

0.1

0.5

0.4 - 0.7

0.4

0.1 - 0.7

0.5

 

0.4 - 0.6

0.7

0.5 - 0.9

Water additive that promotes

 

strong teeth; erosion of natural

 

 

 

 

 

 

 

 

 

 

 

 

 

 

deposits

Nitrate (as N)

ppm

10

10

0.4

ND

ND - ND

ND

ND - ND

ND

 

ND - 0.4

ND

ND - 0.4

Runoff and leaching from

 

fertilizer use; erosion of natural

 

 

 

 

 

 

 

 

 

 

 

 

 

 

deposits

Selenium

ppb

50

30

5

ND

ND - ND

ND

ND - ND

ND

 

ND - ND

ND

ND - 6

Erosion of natural deposits;

 

refineries, mines, and chemical

 

 

 

 

 

 

 

 

 

 

 

 

 

 

waste discharge

* Note: Optimal Fluoride Level as established by US Dept. of Health and Human Services and the State Water Resources Control Board is 0.7 ppm.

Primary standards (MCLs) are developed for the purpose of protecting the public from possible health risks associated with long-term exposure to contaminants. In this table there are five primary standards listed, which means that of the many primary standards set by DDW and the EPA, only these were detected at or above the DLR in San Diego’s drinking water. These results are significantly below their respective MCLs. In general, no health hazard is expected to exist when contaminant levels are below a Primary MCL. A list of the parameters which were analyzed for, but not detected, in San Diego’s drinking water is posted at sandiego. gov/public-utilities/water-quality/water-quality-reports.

California state law requires water agencies with more than 10,000 water service connections to supplement naturally-occurring fluoride in their drinking water. Our water system complies with this requirement to help prevent dental cavities in consumers. In 2020, the City of San Diego’s source waters contained naturally- occurring fluoride between 0.1 and 1.0 ppm. State regulations require water producers to supplement this naturally-occurring fluoride to an optimum dose of 0.7 ppm. In 2020 treated water had fluoride concentrations ranging from 0.1 to 0.9 ppm, with average values of 0.4 to 0.7 ppm. Information about fluoridation, oral health, and current issues is available at cdc.gov/fluoridation/index.html.

 

 

 

 

 

 

CITY OF SAN DIEGO TREATMENT PLANTS

 

 

PURCHASED

 

 

 

 

PHG

 

ALVARADO^

MIRAMAR^

 

OTAY^

TREATED WATER

MAJOR SOURCES

RADIOACTIVE PARAMETERS

UNITS

MCL

(MCLG)

DLR

AVERAGE

RANGE

AVERAGE

RANGE

AVERAGE

 

RANGE

AVERAGE

 

RANGE

IN DRINKING WATER

Gross Alpha Particle Activity

pCi/L

15

(0)

3

ND

ND - 5

3

Single Sample

3

 

Single Sample

ND

 

ND - 3

Erosion of natural deposits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Gross Beta Particle Activity

pCi/L

50*

(0)

4

ND

ND - 6

5

Single Sample

5

 

Single Sample

ND

 

ND - 5

Decay of natural and man-

 

 

made deposits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Radium 228

pCi/L

----

0.019

1

ND

ND - ND

ND

Single Sample

ND

 

Single Sample

ND

 

ND - 1

Erosion of natural deposits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Uranium

pCi/L

20

0.43

1

2

2 - 2

1

Single Sample

ND

 

Single Sample

1

 

ND - 2

Erosion of natural deposits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

* The State Water Resources Control Board

considers

50 pCi/L to be

the level of concern for beta particles.

 

^ Data from

2020. Miramar and Otay Uranium and Radium 228 data from 2017.

 

 

As water travels over the surface of the land or in underground aquifers, it dissolves naturally-occurring minerals and, in some cases, radioactive material. Radioactive materials can be naturally-occurring or a result of oil and gas mining activities. The results in the table above are presented in units of picocuries per

liter (pCi/L), a standard measurement that represents an amount of radiation per liter of water. San Diego’s drinking water is substantially lower than the MCL for all radioactive parameters.

MICROBIOLOGICAL

UNITS

MCL

MCLG

DLR

Total Coliform Bacteria

%

5%

0

n/a

State Total Coliform Rule

Positive

Positive

 

 

*Based on Monthly Percentages of Positive Total Coliform samples

CITY OF SAN DIEGO DISTRIBUTION SYSTEM

AVERAGE*

RANGE*

0.2%

0 - 0.74%

 

 

MAJOR SOURCES IN

DRINKING WATER

Naturally present in the environment

We are required to monitor your drinking water for specific contaminants on a regular basis. Results of regular monitoring are an indicator of whether your drinking water meets health standards. During December 2019 through April 2020, 139 of the 2,706 required distribution system sample sites were not monitored for total coliform and E. coli for reasons outside of our control. Therefore, we cannot be sure of the quality of the drinking water in the associated pressure zones during the weeks these sites were not monitored. However, we have since taken the required samples and put in place policies and tools to safeguard against similar occurrences in the future. Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially-harmful bacteria may be present in the water supply.

DDW regulations require the City to test a minimum of 85 samples per week throughout our distribution system for total coliform bacteria, and to report the results, including the percentage of total coliform positive samples in a given month. To meet this requirement, in 2020 the City of San Diego collected and analyzed 6,784 total

coliform samples from the distribution system, an average of 130 per week. The test also examines the presence of E. coli, which is a subgroup of total coliform. The MCL for total coliform is the presence of coliform in 5% or more of the samples analyzed in one month, meaning that if 100 samples are collected in March and five contain total coliform, a violation of the MCL has occurred. The regulations are written as a percentage of monthly samples because multiple variables can cause a positive result, including localized contamination at the tap. In 2020, the City did not exceed the monthly MCL for total coliform. In fact, this has never occurred in the City’s system since this rule was established in 1989. The maximum value recorded in 2020 was 0.74 percent of monthly samples. When any sample tests positive for total coliform, three additional samples associated with that site are collected and the cause of the positive result is investigated.

Total Coliform Rule testing also examines the presence of E. coli, which is a subgroup of Total Coliform. All samples obtained from our distribution system in 2020 were absent of E. coli.

TURBIDITY

UNITS

MCL

PHG

Turbidity

NTU

TT = 1 NTU

n/a

 

 

TT = 95%

n/a

 

 

 

 

of samples

 

 

≤ 0.3 NTU

 

CITY OF SAN DIEGO TREATMENT PLANTS

PURCHASED

ALVARADO

MIRAMAR

OTAY

TREATED WATER

Max Level Found = 0.20

Max Level Found = 0.10

Max Level Found = 0.08

Max Level Found = 0.09

100% of samples ≤ 0.3

100% of samples ≤ 0.3

100% of samples ≤ 0.3

100% of samples ≤ 0.3

 

 

 

 

MAJOR SOURCES IN DRINKING WATER

Soil runoff

Turbidity is a measure of the cloudiness of the water and is regulated as a Treatment Technique (TT) – an indicator of the effectiveness of our treatment. The City’s three water treatment plants (WTPs) monitor turbidity every 15 minutes to ensure consistent, high-quality drinking water production for our customers.

  1. performance goals established by DDW state that all samples should have turbidity less than 1 NTU, and 95% of the samples should have turbidity less than 0.3 NTU. All three of our treatment plants had 100% of turbidity values less than 0.3 NTU; the maximum values measured in 2020 were 0.20 NTU for Alvarado WTP, 0.10 NTU for Miramar WTP and 0.08 for Otay WTP. These consistent and very low turbidity results have led

to our treatment plants receiving performance awards. For example:

  • The Otay WTP has been awarded the Director’s Award from the American Water Works Association (AWWA) Partnership for Safe Water (PSW) Program for thirteen consecutive years.
  • The Miramar WTP has received the Director’s Award for nine years and the President’s Award for eight consecutive years.
  • Our award-winning Alvarado Treatment Plant participates in the PSW program, meeting all turbidity standards.

10 Annual Drinking Water Quality Report 2020

CONTINUED: PRIMARY STANDARDS (MANDATORY HEALTH RELATED STANDARDS)

 

 

 

 

 

SAMPLES TAKEN FROM CUSTOMER TAPS

 

Number of

 

LEAD AND

 

ACTION

 

 

90th PERCENTILE

SAMPLING SITES

NUMBER

VIOLATION

Schools Sampled

 

COPPER STUDY

UNITS

LEVEL

PHG

DLR

CONCENTRATION

EXCEEDING AL

for Lead

MAJOR SOURCES IN DRINKING WATER

 

 

Copper

ppm

1.3

0.3

0.05

0.4

54

0

NO

281*

 

Internal corrosion of household plumbing systems

 

 

 

 

 

 

 

 

 

 

 

Lead

ppb

15

0.2

5

ND

54

0

NO

 

Internal corrosion of household plumbing systems

 

 

Note: Lead and Copper Rule Monitoring mandated every three years. Most recent monitoring conducted in 2020.

In addition to the EPA Lead and Copper study and schools sampling, the City of San Diego analyzed 72 samples from our three drinking water treatment plants in 2020. All results were below the DLR. * Represents total number of schools sampled in 2017, 2018, and 2019.

Lead and copper are at Non Detectable levels in the water produced at San Diego’s water treatment plants, but can enter drinking water through plumbing materials used in homes or businesses. Exposure to lead and copper may cause health problems ranging from stomach distress to brain damage. In 1991, the EPA published the Lead and Copper Rule (LCR) which, along with corrosion control and other treatment practices, requires monitoring of lead and copper at customer taps. The purpose of the LCR residential sampling is to assess the potential of lead and copper to leach into drinking water from the plumbing installed between the water meter and the tap in homes and businesses. If lead concentrations at customer taps exceed an Action Level (AL) of 15 ppb or copper concentrations exceed an AL of 1.3 ppm in more than 10% of taps sampled, we are required to inform the public and undertake a number of additional actions to ensure comprehensive corrosion control.

If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. The City of San Diego is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds

to two minutes before using water for drinking or cooking. If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline at 1-800-426-4791 or at https://www.epa.gov/lead.

Lead and Copper Rule monitoring must be conducted every three years. In 2020 54 customers provided samples from their taps to the City of San Diego for lead and copper analysis. None of the residences had a copper or lead result above the AL. Because less than 10% of our results were above the AL for both lead and copper, our water is considered non-corrosive, and no additional actions are required. Our next system-wide study will be conducted in the summer of 2023.

In 2017, DDW issued a Permit Amendment requiring water utilities to sample for lead in the drinking water of any school requesting testing. Additionally, Assembly Bill 746 was signed into law in October 2017, requiring California water providers to conduct lead testing at public K-12 schools within their service area to determine if lead is present in the school’s private plumbing or water fixtures. The table lists the total number of schools the Public Utilities Department has tested under these programs. To obtain testing results from individual schools, please contact the school directly or visit the district website.

DETECTED DISINFECTION BYPRODUCTS, DISINFECTANT RESIDUAL AND DISINFECTION BY-PRODUCT PRECURSORS

 

 

 

 

 

 

 

CITY OF SAN DIEGO TREATMENT PLANTS

 

PURCHASED

 

 

 

 

 

 

 

ALVARADO

MIRAMAR

OTAY

TREATED WATER

MAJOR SOURCES IN

 

 

UNITS

MCL

PHG

DLR

AVERAGE

RANGE

AVERAGE

RANGE

AVERAGE

RANGE

AVERAGE

 

RANGE

DRINKING WATER

Bromate*

 

ppb

10

0.1

5.0/1.0***

ND

ND - 9.7

ND

ND - ND

n/a

n/a

2.7

 

ND - 7.4

Byproduct of drinking

 

 

water disinfection

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chlorate

 

ppb

NL=800 PPB

20

n/a

n/a

n/a

n/a

173

95.1 - 334

145

 

34 - 290

Byproduct of drinking

 

 

water disinfection

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chlorite**

 

ppm

1.0

0.05

0.020

n/a

n/a

n/a

n/a

0.35

0.17 - 0.62

n/a

 

n/a

Byproduct of drinking

 

 

water disinfection

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Various natural and

Total Organic Carbon (TOC)

ppm

TT

n/a

0.3

3.1

2.5 - 3.8

2.7

2.0 - 4.2

3.8

2.0 - 5.4

2.5****

 

1.9 - 2.6

manmade sources; TOC is a

 

precursor for the formation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

of disinfection byproducts

* Required for Alvarado, Miramar, and

Purchased Treated Water; compliance is determined by the quarterly Running Annual Average (RAA)

 

 

 

 

 

 

 

** Required for Otay

***City of San Diego DLR= 5, Purchased Treated Water DLR = 1

****Highest Running Annual Average

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MCL

PHG

DLR

 

 

CITY OF SAN DIEGO DISTRIBUTION SYSTEM

 

 

 

MAJOR SOURCES IN

 

 

UNITS

[MRDL]

[MRDLG]

(MDL)

 

 

 

 

 

 

 

 

 

DRINKING WATER

Disinfectant Residual

 

ppm

[4.0]B

[4]

(0.1)

Distribution system average = 2.0

Range = ND - 3.8

----

 

Drinking water disinfectant

(Chloramines as Cl2)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

added for treatment

ChloriteA

 

ppm

1.0

0.05

0.020

Distribution system average = 0.32

Range = 0.14 - 0.44

----

 

Byproduct of drinking water

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

disinfection

Haloacetic Acids (HAA5)

ppb

60C

n/a

----

 

Maximum LRAA = 14

 

Range = ND - 22

Violation - NO

Byproduct of drinking water

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

disinfection

Total Trihalomethanes (TTHMs)

ppb

80C

n/a

----

 

Maximum LRAA = 46

 

Range = 8.8 – 65.6

Violation - NO

Byproduct of drinking water

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

chlorination

  1. Chlorite monitoring required only in the Southern section of the distribution system.
  2. Compliance is determined by the distribution system average.
  3. Total Trihalomethane and HAA5 compliance is based on quarterly Locational Running Annual Averages (LRAA)

Drinking water must be disinfected to ensure that any potentially harmful microbes are neutralized. There are a variety of disinfection strategies used throughout the United States. San Diego utilizes some of the more advanced disinfection technologies available. Our Alvarado and Miramar water treatment plants use ozone and chloramines for disinfection. Ozone produces fewer disinfection byproducts than chlorine or chloramines alone and is considered a superior disinfection method. However, all disinfectant strategies have the potential to create a byproduct. When ozone is used, bromate is monitored as a disinfection byproduct. The City’s Otay WTP uses chlorine dioxide and chloramines for disinfection. When chlorine dioxide is used, chlorite is monitored as a disinfection byproduct in the plant effluent and distribution system. All 2020 results for bromate and chlorite are below the MCLs. Total Organic Carbon (TOC) has no health effects. It is monitored and reported here because it provides an assessment of potential disinfection byproduct formation.

As drinking water travels from the City’s WTPs through the distribution system to homes and businesses, a disinfectant residual must be maintained in order to prevent growth of potentially harmful microbes.

In San Diego, chloramines are used for this purpose. The City performs frequent and comprehensive monitoring to ensure that disinfectant levels remain in the proper range throughout our large and complex distribution system. The Maximum Residual Disinfectant Level (MRDL) is 4.0 ppm. In 2020 the City analyzed 7751 samples for chloramines throughout the distribution system; the average residual was 2.0 ppm and the maximum was 3.8 ppm.

Another category of disinfection byproducts that the EPA and DDW regulate are Total Trihalomethanes (THMs) and Haloacetic Acids (HAA5). Compliance with EPA’s Stage 2 Disinfection ByProduct (DBP) rule is based on the running annual average at each location monitored in the distribution system. The MCL for THMs is an LRAA of 80 ppb, and the MCL for HAA5 is an LRAA of 60 ppb. The City has had no violations of the EPA Stage 1 and Stage 2 DBP MCLs since the program was formalized in 2002. In 2020, our highest LRAA for TTHM was 46 ppb, and individual measurements ranged from 8.8 to 65.6 ppb. For HAA5, our highest LRAA was 14 ppb, and individual measurements ranged from ND to 22 ppb.

Annual Drinking Water Quality Report 2020 11

SECONDARY STANDARDS (AESTHETICS STANDARDS)

 

 

 

 

 

CITY OF SAN DIEGO TREATMENT PLANTS

 

 

PURCHASED

 

 

 

CA

DLR

ALVARADO

MIRAMAR

 

OTAY

TREATED WATER

 

 

UNITS

SMCL

(MDL)

AVERAGE

RANGE

AVERAGE

RANGE

AVERAGE

 

RANGE

AVERAGE

RANGE

MAJOR SOURCES IN DRINKING WATER

Aluminum

ppb

200

50

ND

ND - ND

ND

ND - ND

ND

 

ND - ND

ND

ND - 200

Erosion of natural deposits; residue from

 

some surface water treatment processes

 

 

 

 

 

 

 

 

 

 

 

 

 

Chloride

ppm

500

(0.5)

99.5

88.0 - 108

93.9

80.5 - 103

139

 

103 - 180

79.2

54.0 - 100

Runoff/leaching from natural deposits;

 

seawater influence

 

 

 

 

 

 

 

 

 

 

 

 

 

Color

CU

15

(1)

ND

ND - 2

ND

ND - 1

1

 

ND - 3

ND

ND - 2

Naturally - occurring organic materials

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Odor - Threshold

OU

3

1

ND

ND - 1

ND

ND - ND

1

 

1 - 1

ND

ND - 2

Naturally - occurring organic materials

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Specific Conductance

μS/cm

1,600

n/a

831

769 - 859

777

563 - 923

923

 

845 - 1040

647

292 - 956

Substances that form ions when in water;

 

seawater influence

 

 

 

 

 

 

 

 

 

 

 

 

 

Sulfate

ppm

500

0.5

155

123 - 176

144

72.8 - 202

135

 

89.5 - 187

92.0

12.0 - 208

Runoff/leaching from natural deposits;

 

industrial wastes

 

 

 

 

 

 

 

 

 

 

 

 

 

Total Dissolved Solids

ppm

1000

(10)

515

468 - 553

477

352 - 564

556

 

506 - 620

345

140 - 588

Runoff/leaching from natural deposits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Secondary standards (Secondary MCLs) are set to protect the odor, taste, and appearance of drinking water. If present at or above the Secondary MCL, these parameters may cause the water to appear cloudy or colored, or to have a different or unusual taste or odor. These parameters are not considered to present

a risk to human health at or above Secondary MCL levels. All measurements of Secondary Standards were at or below the Secondary MCL in 2020.

OTHER PARAMETERS THAT MAY BE OF INTEREST

 

 

 

 

 

 

 

 

CITY OF SAN DIEGO TREATMENT PLANTS

 

 

PURCHASED TREATED WATER

 

 

 

 

 

ALVARADO

 

 

MIRAMAR

 

 

OTAY

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UNITS

MCL

PHG

MDL

AVERAGE

RANGE

 

AVERAGE

RANGE

AVERAGE

RANGE

AVERAGE

RANGE

Sodium

ppm

n/a

n/a

20

87.6

75.9 -93.2

 

81.8

62.5

- 90.3

105

95.0 - 128

68.4

45.4 - 98.0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Total Hardness

ppm

n/a

n/a

10

236

203

- 255

 

218

127

- 277

235

175

- 293

145

41.7 - 273

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Total Hardness

gr/Gal

n/a

n/a

0.6

13.8

11.9

- 14.9

 

12.7

7.42

- 16.2

13.7

10.2

- 17.1

8.47

2.44 - 15.9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Alkalinity - Total as CaCO3

ppm

n/a

n/a

20

126

112

- 150

 

112

83.2 - 139

125

110

- 144

91.5

46.0 - 121

pH

pH

n/a

n/a

n/a

8.06

6.84

- 8.46

 

8.20

7.59

- 8.61

8.18

7.46

- 8.74

8.14

7.40 - 8.80

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Water quality parameters that may be of interest to our consumers, but do not have MCLs or PHGs and are not considered to present a risk to human health, are included in the table above. Although sodium and hardness do not have MCLs, they are of interest to many consumers who are concerned about sodium intake and may believe that the hardness of the water could affect their health. Therefore, monitoring and

reporting are required by DDW. Sodium refers to the salt present in the water and is generally naturally occurring. Hardness is the sum of positively-charged mineral ions present in the water, essentially the sum of magnesium and calcium. These minerals are usually naturally occurring. Alkalinity and pH are included here because they have proven to be of interest to our customers.

DETECTED UNREGULATED PARAMETERS

 

 

NOTIFICA-

 

 

CITY OF SAN DIEGO TREATMENT PLANTS

 

PURCHASED TREATED WATER

 

 

TION

DLR

ALVARADO

MIRAMAR

 

OTAY

 

 

 

UNITS

LEVEL

(PHG)

AVERAGE

RANGE

AVERAGE

RANGE

AVERAGE

RANGE

AVERAGE

RANGE

Boron

ppm

1

0.1

0.1

0.1 - 0.1

0.1

0.1 - 0.1

0.2

0.2 - 0.2

0.3

0.1 - 0.8

 

 

 

 

 

 

 

 

 

 

 

 

N-Nitrosodimethylamine (NDMA)

ppt

10

(3)

n/a

n/a

n/a

n/a

n/a

n/a

2

ND - 4.2

 

 

 

 

 

 

 

 

 

 

 

 

Chromium, hexavalent (CrVI)

ppb

----

(0.02)*

0.06

Single Sample

0.05

Single Sample

0.03

Single Sample

ND

ND - ND

 

 

 

 

 

 

 

 

 

 

 

 

* The DLR of 1 ppb and the MCL of 10 ppb for Chromium VI were repealed in 2017. The value listed here is the PHG for Chromium VI.

UCMR4 STUDY

 

 

UCMR4

 

 

CITY OF SAN DIEGO TREATMENT PLANTS

 

 

CITY OF SAN DIEGO

 

 

MRL

ALVARADO

 

MIRAMAR

 

 

OTAY

DISTRIBUTION SYSTEM

UCMR4 PARAMETERS1

UNITS

(MDL)

AVERAGE

RANGE

 

AVERAGE

RANGE

AVERAGE

RANGE

MAX LRAA

 

RANGE

Bromide*

ppm

(0.02)

0.10

0.05 - 0.16

 

0.06

0.04

- 0.11

0.20

0.04 - 0.35

n/a

 

n/a

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Manganese

ppb

0.4

2.2

ND - 8.2

 

0.9

0.6

- 1.2

0.2

ND - 0.7

n/a

 

n/a

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Total Organic Carbon (TOC)*

ppm

(1)

3.2

2.7 - 3.7

 

2.7

2.6

- 2.9

4.9

2.6 - 7.0

n/a

 

n/a

 

 

 

 

 

 

 

 

 

 

 

 

 

HAA9**

ppb

n/a

n/a

n/a

 

n/a

n/a

n/a

n/a

26

 

4.1 - 40

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 UCMR4 samples were collected in 2018

* As measured in untreated plant influent

** HAA9 is the sum of bromochloroacetic acid, bromodichloroacetic acid, chlorodibromoacetic acid, dibromoacetic acid, dichloroacetic acid, monobromoacetic acid, monochloroacetic acid, tribromoacetic acid, and trichloroacetic acid.

The parameters listed in the Detected Unregulated Parameters section are not regulated by DDW or the EPA, and monitoring is not required. Unregulated contaminant monitoring helps U.S. EPA and the State Water Resources Control Board to determine where certain contaminants occur and whether the contaminants need to be regulated. Boron and N-Nitrosodimethylamine (NDMA) have been issued Notification Levels (NL) by DDW. If detected above the NL, customers must be notified of the presence of these parameters. The results presented here are significantly lower than the NL. Hexavalent Chromium (CrVI) was issued an MCL of 10 ppb and a DLR of 1 ppb by DDW in 2014. However, these were withdrawn in 2017. The values presented here are approximately 100 times less than 10 ppb.

As part of the 1996 Safe Drinking Water Act (SDWA) amendments, every five years EPA selects from the Contaminant Candidate List (CCL) up to 30 unregulated contaminants to be monitored by public water systems as part of the

Unregulated Contaminant Monitoring Rule (UCMR) program. The CCL is a list of contaminants that are not regulated but are known or anticipated to occur in public water systems, and may warrant future regulation under the Safe Drinking Water Act. The results of UCMR studies provide a basis for future regulatory actions to protect public health. The City of San Diego conducted UCMR4 sampling in 2018.

San Diego’s drinking water was tested by an EPA-approved contract laboratory in 2018 for 30 UCMR4 unregulated contaminants. This included 10 different cyanotoxins, none of which were detected. Twenty additional chemicals were monitored, including metals, pesticides, and alcohols. Of these 32 parameters, two were detected – manganese and HAA9. Additionally, two indicators of water quality were monitored in untreated water – bromide and Total Organic Carbon (TOC).

Public Utilities Department

9192 Topaz Way

San Diego, CA 92123

Quality | Value | Reliability | Customer Service

PRESORTED

STANDARD

U.S. POSTAGE

PAID

SAN DIEGO, CA PERMIT 134

This report contains important information about your drinking water. Translate it, or speak with someone who understands it.

Spanish

Este informe contiene información muy importante sobre su agua potable.

Tradúzcalo o hable con alguien que lo entienda bien.

Arabic

Chinese (Traditional)

Chinese (Simplified)

Farsi

French

Cé rapport contient des information importantes concernant votre eau potable. Veuillez traduire, ou parlez avec quelqu’ un qui peut le comprendre.

Hmong

Daimntawv tshaj tawm no muaj lus tseemceeb txog koj cov dej haus.

Tshab txhais nws, los yog tham nrog tej tug neeg uas totaub txog nws.

JapaneseKhamer

Korean

Laotian

Russian

Swahili

Shauri hii niya kufahamisha uzuri wa maji ya kunyua.

Shauri nilazima egeuzwe kwa yoyote hajui Kiingereza.

Tagalog

Mahalaga ang impormasyong ito. Mangyaring ipasalin ito.

Vietnamese

This information is available in alternative formats upon request.

Printed on recycled paper

Contaminants


Otay Water District

EWG's drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group by the California State Water Resources Control Board, as well as information from the U.S. EPA Enforcement and Compliance History database (ECHO). For the latest quarter assessed by the U.S. EPA (January 2019 - March 2019), tap water provided by this water utility was in compliance with federal health-based drinking water standards.

Utility details

  • Serves: 213000
  • Data available: 2012-2017
  • Data Source: Purchased surface water
  • Total: 18

Contaminants That Exceed Guidelines

  • Bromodichloromethane
  • Bromoform
  • Chloroform
  • Chromium (hexavalent)
  • Dibromochloromethane
  • Dichloroacetic acid
  • Total trihalomethanes (TTHMs)
  • Trichloroacetic acid

Other Detected Contaminants

  • Bromochloroacetic acid
  • Chlorate
  • Dibromoacetic acid
  • Fluoride
  • Haloacetic acids (HAA5)
  • Molybdenum
  • Monochloroacetic acid
  • Strontium
  • Uranium
  • Vanadium

Reminder

Always take extra precautions, the water may be safe to drink when it leaves the sewage treatment plant but it may pick up pollutants during its way to your tap. We advise that you ask locals or hotel staff about the water quality. Also, note that different cities have different water mineral contents.

Sources and Resources

Sources Cited

Is San Diego Tap Water Safe to Drink?

Yes, San Diego's tap water is generally considered safe to drink as it met the EPA’s water quality mandates in its 2020 Water Quality Report. From April 1, 2018 to June 30, 2021 San Diego Water Utility had one Safe Drinking Water Act Violation, which a monitoring violation, and has been resolved. One should not get sick from drinking San Diego tap water. 

Though San Diego's tap water is generally safe to drink, one should consider the possible safety impacts of low levels of regulated contaminants, unregulated contaminants, and water quality issues caused by severe weather.

While San Diego's tap water is generally safe to drink, long-term residents may consider using water filters for their everyday drinking, as the EPA is still assessing the health impacts of long-term exposure to certain contaminants that they do not yet have regulations for, and long term exposure to certain contaminants which are already regulated, but below the currently acceptable levels. 

Where Does San Diego Tap Water Come From?

According to San Diego's 2020 Water Quality Report, the City of San Diego currently imports most of its water supply, the bulk of which is raw (untreated) water purchased from the San Diego County Water Authority. All raw water is treated before entering the City’s drinking water distribution system. Less than 10% of the imported water purchased from the County Water Authority is a blend of treated water from the Metropolitan Water District’s Skinner Water Treatment Plant, the County Water Authority’s Twin Oaks Valley Water Treatment Plant and the Carlsbad Desalination Plant. Most of the imported water from the County Water Authority is a blend from the Colorado River and State Water Project (see map to the left). Throughout the year, the ratio of water from each source changes. The constituents that make up the City’s source water are influenced by the water source, climate, geology and the land activities that they flow through. The City continually monitors our source water and adjusts its treatment process to ensure that the water is always healthy and safe.

Main Contaminants Found in San Diego Tap Water

As we mentioned above, San Diego tap water meets the requirements set by the EPA. For more precise information please see their 2020 water quality report. Though San Diego drinking water meets EPA standards that does not mean it is contaminant free as there are levels that the EPA considers acceptable. Though the EPA regulated contaminants must meet a certain threshold for the city’s water to be deemed acceptable, many are still present in the drinking water at some level. The EPA continues to evaluate the long term impacts of these chemicals as more research is available. For example, the rules around arsenic, as well as, lead and copper are currently being re-evaluated.

Additionally, there are a number of “emerging” contaminants that the EPA has not determined acceptable levels for and is currently researching. For example, Per- and polyfluoroalkyl substances (PFAS), for which the EPA has issued a health advisory. PFAS are also called ‘forever chemicals’ since they tend not to break down in the environment or the human body and can accumulate over time. We do not yet fully understand the dangers of PFAS as they are currently being investigated. San Diego has at least one suspected PFAS leak, so there is potential that they could have made their way into San Diego's drinking water.

Lead piping is another potential source of contamination for many homes, both through service lines and in your home. The National Resource Defense Council has a great walk-through on how to determine if you may have lead service lines.

So while San Diego's tap water does meet the requirements set by the EPA, it still makes sense to try to purify the tap water further to reduce contaminants to lower levels.

Is San Diego Tap Water Safe to Drink?

Yes, San Diego’s tap water is generally considered safe to drink as it met the EPA’s water quality mandates in its 2020 Water Quality Report. From April 1, 2018 to June 30, 2021 San Diego Water Utility had one Safe Drinking Water Act Violation, which a monitoring violation, and has been resolved. One should not get sick from drinking San Diego tap water. 

Though San Diego’s tap water is generally safe to drink, one should consider the possible safety impacts of low levels of regulated contaminants, unregulated contaminants, and water quality issues caused by severe weather.

While San Diego’s tap water is generally safe to drink, long-term residents may consider using water filters for their everyday drinking, as the EPA is still assessing the health impacts of long-term exposure to certain contaminants that they do not yet have regulations for, and long term exposure to certain contaminants which are already regulated, but below the currently acceptable levels. 

Where Does San Diego Tap Water Come From?

According to San Diego’s 2020 Water Quality Report, the City of San Diego currently imports most of its water supply, the bulk of which is raw (untreated) water purchased from the San Diego County Water Authority. All raw water is treated before entering the City’s drinking water distribution system. Less than 10% of the imported water purchased from the County Water Authority is a blend of treated water from the Metropolitan Water District’s Skinner Water Treatment Plant, the County Water Authority’s Twin Oaks Valley Water Treatment Plant and the Carlsbad Desalination Plant. Most of the imported water from the County Water Authority is a blend from the Colorado River and State Water Project (see map to the left). Throughout the year, the ratio of water from each source changes. The constituents that make up the City’s source water are influenced by the water source, climate, geology and the land activities that they flow through. The City continually monitors our source water and adjusts its treatment process to ensure that the water is always healthy and safe.

Main Contaminants Found in San Diego Tap Water

As we mentioned above, San Diego tap water meets the requirements set by the EPA. For more precise information please see their 2020 water quality report. Though San Diego drinking water meets EPA standards that does not mean it is contaminant free as there are levels that the EPA considers acceptable. Though the EPA regulated contaminants must meet a certain threshold for the city’s water to be deemed acceptable, many are still present in the drinking water at some level. The EPA continues to evaluate the long term impacts of these chemicals as more research is available. For example, the rules around arsenic, as well as, lead and copper are currently being re-evaluated.

Additionally, there are a number of “emerging” contaminants that the EPA has not determined acceptable levels for and is currently researching. For example, Per- and polyfluoroalkyl substances (PFAS), for which the EPA has issued a health advisory. PFAS are also called ‘forever chemicals’ since they tend not to break down in the environment or the human body and can accumulate over time. We do not yet fully understand the dangers of PFAS as they are currently being investigated. San Diego has at least one suspected PFAS leak, so there is potential that they could have made their way into San Diego’s drinking water.

Lead piping is another potential source of contamination for many homes, both through service lines and in your home. The National Resource Defense Council has a great walk-through on how to determine if you may have lead service lines.

So while San Diego’s tap water does meet the requirements set by the EPA, it still makes sense to try to purify the tap water further to reduce contaminants to lower levels.

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