San Mateo, California

Water Quality in San Mateo, California

Watershed: Cordilleras Creek – Frontal San Francisco Bay Estuaries

What is the water quality like in San Mateo, CA?

Let’s dive deeper into what’s in San Mateo water.

What’s in San Mateo water?

Here are the top 5 chemical compounds in your water and what health issues they can potentially cause:

1. Bromodichloromethane – Potential effect: Cancer
2. Chloroform – Potential effect: Cancer
3. Haloacetic acids – Potential effect: Cancer
4. Hexavalent Chromium – Potential effect: Cancer
5. Total trihalomethanes – Potential effect: Cancer

These are five of the 19 contaminants analyzed by the Environmental Working Group (ewg.org).

8 of these contaminants are rated as exceeding EWG Health Guidelines.

See the What Can You Do? section below for all of the contaminants you can filter out and how to do it.

Where does San Mateo’s water come from?

San Mateo’s water comes from the Cordilleras Creek – Frontal San Francisco Bay Estuaries watershed.

One of the EPA assessed water sources in the Cordilleras Creek – Frontal San Francisco Bay Estuaries watershed is in Impaired or Unknown condition. This is Laurel Creek.

Ideally, a water source would be rated in Good condition. Bear Gulch Reservoir and Redwood Creek are in Good condition.

Whether a water source is in Impaired or Good condition refers to the quality of these uses:

1. Drinking Water
2. Aquatic Life
3. Fish and Shellfish Consumption
4. Recreation

Learn more from How’s My Waterway

See below for what you can do to improve San Mateo’s water.

Conclusion – What Can You Do?

Information about water quality can be surprising.

But there’s no reason to lose hope. There are things you can do in your household as well as things you can do at a community level.

In Your Household:

• Use Berkey filters with activated carbon to filter out 17 of the 19 contaminants in your drinking water. (Berkey Light and Travel Berkey are the only types available in California.)
  • Berkey filters can also remove up to 99.99% of Lead in San Mateo water.
  • Brita can filter 12 contaminants (and Lead depending on the filter).
  • Note: We may receive a commission if you decide to purchase filters through links on this page.
• To filter out 23 of the 19 contaminants, consider a Reverse Osmosis water filtration system for your house.
  • These are more expensive than pitchers to purchase, but can be more effective.
  • They have the benefit of filtering out heavy hitters like:
    • Aluminum
    • Bromide
    • Bromodichloromethane – health risks in drinking water
    • Bromoform
    • Chloroform – side effects
    • Chromium (total)
    • Dibromoacetic acid
    • Dibromochloromethane
    • Dichloroacetic acid
    • Fluoride
    • Haloacetic acids – chlorination byproduct*
    • Hexavalent chromium – health effects
    • Molybdenum
    • Monochloroacetic acid
    • Strontium
    • Total trihalomethanes – byproduct of chlorination*
    • Trichloroacetic acid

*Chlorination is an effective method of disinfecting/treating drinking water. You can then use a water filter to reduce the effects of chlorination byproducts to get the safest, cleanest water possible.

In Your Community:

Contact your local government officials and put pressure on them to invest in cleaner waterways and upgraded city water filtration and treatment.

Go to: https://cityofsanmateo.org/ to find contact information for your local officials.

Water Quality in Other California Cities

California Water Quality Page