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Is Patterson, CA tap water safe?

2 utilities serve Patterson, by EPA’s records. Here is what EPA’s and California’s records show for each, against the legal limits and the stricter health goals.

Matched to your utility using EPA records.

The short answer

1 of the 2 utilities serving Patterson has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records: Western Hills Water District/Diablo Gran.

City of Patterson, which serves the most people here, has 3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 74 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.

The water from City of Patterson is very hard, typically 400 mg/L (23.4 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 Patterson’s ZIP codes, from EPA’s estimates.

What handles it

Each of these is certified, on a certifier’s listing, for a result above a line in City of Patterson’s water, which serves the most people here. Another utility’s report names what handles its own results.

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Every claim, and more filters, in the full report

Water testing near Patterson

A utility tests the water it sends out. A test of your own tap shows what your pipes add, and on a private well it is the only test there is. It takes a lab California certifies.

The 3 labs California certifies closest to Patterson, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Certified Laboratories - Turlock

    Turlock, CA · about 19 miles

    Certified for bacteria

    (209) 664-1100

  • Institute of Environmental Health, Inc. dba IEH-JL Analytical

    Modesto, CA · about 19 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (209) 538-8111

  • Microbac Laboratories, Inc. - Turlock

    Turlock, CA · about 20 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, radioactivity

    (707) 822-4649

All 145 certified labs for California

ZIP codes in Patterson

Which ZIP codes are in Patterson: 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 Patterson

Other towns in Stanislaus County with a page of their own.

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