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Is Sammamish, WA tap water safe?

3 utilities serve Sammamish, by EPA’s records. Here is what EPA’s and Washington’s records show for each, against the legal limits and the stricter health goals.

Matched to your utility using EPA records.

The short answer

None of the 3 utilities serving Sammamish has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and Washington’s records.

Sammamish Plateau Water & Sewer, which serves the most people here, has 2 results above EPA’s new limit, which takes effect in 2029 and 2 results above the health goal. The worst: PFOS at 11.1 ppt, above EPA’s new limit, which takes effect in 2029.

The water from Sammamish Plateau Water & Sewer is soft to moderately hard depending on the source, 51 to 95 mg/L (3 to 5.6 grains per gallon). How Washington’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 Sammamish’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 Sammamish Plateau Water & Sewer’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 Sammamish

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 Washington certifies.

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

  • OnSite Environmental, Inc.

    Redmond, WA · about 8 miles

    Certified for lead and copper, metals, minerals and other inorganics

    (425) 883-3881

  • AmTest Laboratories

    Renton, WA · about 12 miles

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

    (425) 885-1664

  • Aqua Test, Incorporated

    Maple Valley, WA · about 12 miles

    Certified for bacteria, nitrate

    (425) 432-9360

All 84 certified labs for Washington

ZIP codes in Sammamish

Which ZIP codes are in Sammamish: 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: Washington State Department of Ecology, Lab Accreditation Program, environmental laboratories accredited for drinking water analyses; distances from the Census 2020 ZIP code tabulation area gazetteer.

Near Sammamish

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

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