Is Walnut Creek, CA tap water safe?
The short answer
None of the 3 utilities serving Walnut Creek has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records.
East Bay MUD, which serves the most people here, has 1 result above the health goal. The worst: Uranium at 5.3 ppb, above the health goal. Health goals are stricter than legal limits and are not enforced.
The water from East Bay MUD is soft to moderately hard depending on the source, 17 to 120 mg/L (1 to 7 grains per gallon). How California’s water compares.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Walnut Creek’s ZIP codes, from EPA’s estimates.
- Open report
East Bay MUD
California · serves 1.5 million people · about 41,900 in Walnut Creek
1 result above the health goal. The worst: Uranium at 5.3 ppb, above the health goal. Hardness: soft to moderately hard depending on the source, 17 to 120 mg/L (1 to 7 grains per gallon).
No health-based violations since 2016
- Open report
Contra Costa Water District
California · serves 210,500 people · about 16,300 in Walnut Creek
2 results above the health goal. The worst: Arsenic at 2.5 ppb, above the health goal. Hardness: soft to hard depending on the source, 52 to 132 mg/L (3 to 7.7 grains per gallon).
No health-based violations since 2016
- Open report
Casa Medanos Water System
California · serves 45 people · based in Walnut Creek
1 result above the health goal. The worst: Arsenic at 5.8 ppb, above the health goal. Hardness: very hard, 294 mg/L (17.2 grains per gallon).
No health-based violations since 2016
MUD stands for municipal utility district, a local water and sewer district common in Texas.
Water testing near Walnut Creek
The 3 labs California certifies closest to Walnut Creek, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
McCampbell Analytical, Inc.
Pittsburg, CA · about 11 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, PFAS
Eurofins Built Environment Testing West, LLC
Emeryville, CA · about 14 miles
Certified for lead and copper
Asbestos TEM Laboratories, Inc
Oakland, CA · about 14 miles
Certified for asbestos
Which ZIP codes are in Walnut Creek: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: California State Water Resources Control Board, ELAP accredited laboratories and their fields of accreditation; distances from the Census 2020 ZIP code tabulation area gazetteer.
Near Walnut Creek
Other towns in Contra Costa County with a page of their own.
What to do next
- Read East Bay MUD’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- About UraniumWhat it does to health, where it comes from, and the certification claim that addresses it.About Uranium
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water