Well Water Nerd

Well water testing in Washington

Nobody tests a private well unless the owner does. In Washington, the public record says to start with uranium, PFOS, nitrate, then bacteria every year. Below: what to order, where, what it costs, and the county-by-county results that set the order.

What to test for first

  1. 1
    Uranium
    32% of 1,440 local samples were above the limit.
  2. 2
    PFOS
    19% of 62 local samples were above the limit.
  3. 3
    Nitrate
    18% of 19,233 local samples were above the limit.
  4. 4
    PFOA
    16% of 62 local samples were above the limit.
  5. 5
    Radium (226 + 228)
    16% of 2,201 local samples were above the limit.

Test your Washington well for uranium, PFOS and nitrate

Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.

Order the Tap Score well water test kit, from $209Already tested? Upload the report

Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.

Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.

Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.

Where to get it tested

Three routes, and all of them work. A mail-in kit from a certified lab is the simplest: the lab ships bottles, you fill them at the kitchen tap, and results come back by email. The full panel above is $209.

A local certified lab is the second route. Environmental lab accreditation from Washington State Department of Ecology lists every lab certified for drinking water in Washington. Call ahead: some take walk-in samples, some ship bottles.

Free or low-cost testing: The Washington State Department of Health offers free nitrate and coliform testing to private well households within a specific boundary of the Lower Yakima Valley or Western Benton County, who apply through an online form to see if they qualify. How to get it

For questions about your well, Drinking Water at Washington State Department of Health is the official source.

Already have results? Get the lab report read line by line, $29.

Testing by county

The contaminant most often over its limit in each county's public record, highest share first. Open a county for the full test list and its towns.

CountyTest first forOver the limit
Stevens CountyUranium59%
Whatcom CountyNitrate51%
Franklin CountyNitrate36%
Yakima CountyNitrate26%
Grant CountyNitrate26%
King CountyArsenic18%
Snohomish CountyArsenic16%
Douglas CountyNitrate15%
Benton CountyNitrate15%
Ferry CountyArsenic13%
Whitman CountyNitrate11%
Adams CountyNitrate11%
Kitsap CountyLead10%
Lewis CountyNitrate9%
Walla Walla CountyNitrate9%
Thurston CountyNitrate6%
Pierce CountyArsenic5%
Lincoln CountyNitrate5%
Island CountyNitrate5%
Clark CountyNitrate5%
Okanogan CountyArsenic4%
Chelan CountyNitrate3%
Skagit CountyArsenic3%
Spokane CountyNitrate2%
Cowlitz CountyArsenic2%
Kittitas CountyNitrate1%
Clallam CountyNitrate<1%
Pacific CountyNitrate<1%
Grays Harbor CountyFluoride0%
Klickitat CountyFluoride0%
Mason CountyFluoride0%
Pend Oreille CountyNitrate0%
San Juan CountyFluoride0%

Closer than the county: see the sampled wells near your address.

Free, no obligation

Get on the list for a free in-home water test in Washington

We are signing licensed water treatment companies county by county. They test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Nothing is shared until a company joins for your area, and you get an email naming it first.

What are you worried about?

The test is free and there is no obligation. No company is named yet; your details stay with us until one joins for your area, and we log the time and address of this request.

Common questions

What should I test my well for in Washington?

Start with uranium, PFOS, nitrate. 32% of 1,440 local samples were above the limit. Add total coliform bacteria and nitrate every year for any private well.

Where can I get my well water tested in Washington?

Use a lab certified for drinking water. Washington State Department of Ecology keeps the list of certified labs. A mail-in kit from a certified lab works anywhere in the state.

How much does well water testing cost in Washington?

A full mail-in panel from a certified lab costs $209 (Tap Score well water test kit). A bacteria-only test costs $99 (Tap Score coliform and E. coli test).

Is there free well water testing in Washington?

The Washington State Department of Health offers free nitrate and coliform testing to private well households within a specific boundary of the Lower Yakima Valley or Western Benton County, who apply through an online form to see if they qualify.

How often should a private well be tested?

Bacteria and nitrate every year. A full panel once, then again after flooding, a change in taste, smell or color, work on the well, a new baby in the house, or a nearby result above the limit. Contaminants that come from the rock, like arsenic, radon and uranium, change slowly, so one good test and a check every few years is enough.