Frequently Asked Questions
Below are answers to some of the most frequently asked questions regarding water quality that we receive. If you have other questions about water quality issues, please contact us.
- Where does our water come from?
- Where is our drinking water treated?
- Does the City’s water supply contain fluoride?
- What do you test for in my drinking water, and where can I get those test results?
- What is the hardness of my water?
- Is lead a hazard in our water?
- Does the City test for Cryptosporidium in the water supply? Is there a concern for the general public or for people with compromised immune systems?
- Where does our water come from?
Between 85 and 90% of our drinking water is a blend from the Colorado River and Northern California. About 10 to 15% of the City’s drinking water supply is made up of runoff from local rainfall that is captured in our reservoirs. For more information, see the Water Sources web page.
- Where is our drinking water treated?
The City has three water treatment plants, and where your water is treated depends upon what part of the City you live. South San Diego receives water from the Otay Water Treatment Plant, central San Diego’s water comes from the Alvarado Water Treatment Plant, and north San Diego gets water from the Miramar Water Treatment Plant. For more information, see the Our Water Treatment Process web page.
- Does the City’s water supply contain fluoride?
The City of San Diego began water fluoridation in February 2011. California state law requires water agencies with more than 10,000 water service connections (which includes the City of San Diego) fluoridate their drinking water supplies. If you have health questions or concerns regarding fluoride, please contact your physician and/or dentist. For more information, see the Water Fluoridation web page.
- What do you test for in my drinking water, and where can I get those test results?
The California Department of Public Health requires water agencies to test for certain contaminants. Each year the City publishes its annual “Drinking Water Quality Report” with results from these tests, as well as other useful information. The report and additional Tables 5 and 6, can be found on the Water Quality web page.
- What is the hardness of my water?
Typically, drinking water in San Diego averages about 15.4 grains per gallon (gr/gal), or 263 parts per million (ppm); and, depending upon water demand and the area of the City you live, can range from 13.4 to 19.0 gr/gal, or 229 to 325 ppm. For more information, see the Water Hardness web page