Alliance Technical Group, LLC-Seattle
3600 Fremont Ave N
Seattle, WA 98103
- Coliform bacteria
- Lead
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
Well water testing in King County, Washington
Labs copied from the official Washington certified lab list (last verified 2026-10-29). All Washington labs
The official Washington list shows 15 certified labs in King County. Call before you sample to confirm the lab accepts private well water and to ask about bottles, prices and drop-off times.
Certified labs in King County
AmTest Laboratories
1131 SW 7th Street
Renton, WA 98057
- Nitrate
- Arsenic
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
AmTest Laboratories
1131 SW 7th Street
Renton, WA 98057
- Coliform bacteria
- Lead
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
Analytical Resources, LLC
4611 S 134th Place
Tukwila, WA 98168-3240
- Nitrate
- Lead
- Arsenic
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
Aqua Test, Incorporated
28620 Maple Valley Road SE
Maple Valley, WA 98038
- Coliform bacteria
- Nitrate
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
Brooks Applied Labs, LLC
13751 Lake City Way NE
Seattle, WA 98125
- Lead
- Arsenic
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
Eurofins EPK Built Environment Testing, LLC
7619 6th Avenue NW
Seattle, WA 98117
- Coliform bacteria
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
Friedman & Bruya, Inc.
5500 4th AVE S
Seattle, WA 98108
- Lead
- Arsenic
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
IEH Analytical Laboratories
13751 Lake City Way NE
Seattle, WA 98125
- Nitrate
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
IEH Analytical Laboratories
13751 Lake City Way NE
Seattle, WA 98125
- See state list
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
IEH Analytical Laboratories
13751 Lake City Way NE
Seattle, WA 98125
- Lead
- Arsenic
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
MCL Food Testing
711 6th Ave N
Seattle, WA 98109
- Coliform bacteria
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
NVL Laboratories, Inc
4708 Aurora Ave N
Seattle, WA 98103
- Lead
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
OnSite Environmental, Inc.
14648 NE 95th Street
Redmond, WA 98052
- Lead
- Arsenic
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
Seattle-King Co Dept of Public Health Lab
325 Ninth Ave
Seattle, WA 98104
- Coliform bacteria
Call to confirm the lab accepts private well samples, and ask about price and turnaround.
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What to test for
- Every year, test for total coliform bacteria, nitrate, total dissolved solids and pH, as EPA recommends for private wells. Source
- Nitrate: USGS finds higher nitrate in shallow groundwater under farmland. Parts of Washington are intensively farmed, so test nitrate every year, and before using the water for infant formula. Source
- Arsenic: USGS maps show naturally occurring arsenic in groundwater in parts of Washington and its region. Test at least once, then as your lab or health department advises. Source
- PFAS: test if you live near an airport, military base, landfill, or industrial or firefighting-foam site. EPA explains private well PFAS testing. Source
- After flooding, test for bacteria before drinking the water again, as EPA advises. Source
After a flood in King County
EPA says to test a private well for bacteria after flooding before drinking the water again. Check current flood alerts and Flood Watch, and read flood season testing. EPA: your well after a flood
Local help
Your King County or local health department can tell you about local well testing, including any free or low-cost programs. State contact: Washington State Department of Ecology (lab certification).
Questions
Where can I test well water in King County, WA?
The official Washington certified lab list shows 15 labs in King County; they are listed on this page with phone numbers. Call first to confirm they accept private well samples.
How often should I test my well?
EPA recommends testing every year for total coliform bacteria, nitrates, total dissolved solids and pH, and testing right away after flooding, well repairs, or a change in taste, color or smell.
Other Washington counties
Adams County · Benton County · Clallam County · Clark County · Cowlitz County · Franklin County · Grant County · Grays Harbor County · Kitsap County · Klickitat County · Lewis County · Lincoln County · Okanogan County · Pacific County · Pierce County · Skagit County · Snohomish County · Spokane County · Thurston County · Walla Walla County · Whatcom County · Yakima County