Stockton, California

Stockton, California Stockton, California

What is the Water Quality in Stockton, California?

Compared to other US cities, Stockton water quality ranks in the high range for contamination excluding Lead.

Most of their 38 contaminants have cancer-causing attributes.

  • Arsenic is at extremely high levels: 669x health guidelines.
  • Haloacetic acids (HAA5) are at extremely high levels: 193x health guidelines.
  • Haloacetic acids (HAA9) are at extremely high levels: 463x health guidelines.
    • These are both byproducts of the chlorine treatment process most water supplies go through.
  • PFOA is at very high levels: 80x health guidelines.

Let’s look closer at what’s in Stockton water.

What’s in Stockton water?

Here are the top 6 chemical compounds in your water and what health issues they can potentially cause:

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

These are six of the 38 contaminants analyzed by the Environmental Working Group (

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

Does Stockton have Lead contamination?

No, Stockton does not appear to have lead in its water. The most recent Lead samples collected from 2015 through 2017 showed concentrations of 0.0 parts per billion (ppb).

The legal limit for lead is 15 parts per billion. Being well-below this level is a good thing.

  • Concentrations between 3.8 ppb and 15 ppb put a formula-fed baby at risk of elevated blood lead levels. Read more about the symptoms of Lead in water.

There is no safe level of lead for humans.

  • The good news is that 99.99% of the lead can be removed.

See the What Can You Do? section below to learn how to filter out contaminants.

Where does Stockton’s water come from?

Stockton’s water comes from the McLeod Lake – Mormon Slough watershed.

One of the two EPA assessed water sources in the McLeod Lake – Mormon Slough watershed are in Impaired condition. This is:

  • Mormon Slough from Stockton Diverting Canal to Bellota Weir.

Ideally, a water source would be rated in Good condition. The Stockton Diverting Canal itself is 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 Stockton’s water.

What Can You Do?

Information about water quality in Stockton can be surprising.

But there are things you can do in your home to clean up your water.

To Remove Lead and Other Contaminants In Your Home:

There is one solution that beats Brita, PUR, and expensive whole house systems.

  • It costs less per gallon.
  • Needs fewer filter changes.
  • And it doesn’t make your water taste weird.

Take Control of Your Water with Berkey Filters

  • Use Berkey filters with activated carbon to filter out at least 88% of 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 any Lead in Stockton water.
    • Brita can filter 24 contaminants (63%) 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 35 of the 38 contaminants (92.1%) in your whole house, consider a Reverse Osmosis water filtration system for your home.

*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: to find contact information for your local officials.

Water Quality in Other California Cities

California Water Quality Page

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