Arsenic Water Testing Labs in Washington (33 state-certified labs)
Labs on Washington's official certification list that test drinking water for arsenic, with the ones that take homeowner samples first.
33 named for arsenic itself on the list.
Per the state list or a state web page. Call to confirm.
Located outside Washington but on its list.
USGS estimate for Washington.
How many labs test for arsenic in Washington
33 labs on Washington's official drinking-water lab list are certified to test for arsenic. All 33 are named for arsenic on the list. 32 of them are marked as taking samples from the public. They are listed first. 17 are located outside Washington.
The list is published by the Washington State Department of Ecology - Lab Accreditation Program (with WA DOH). List version on file: Information current as of 11/13/2026. Fetched 2026-11-15 (UTC).
Washington labs certified for arsenic
Marked as taking public samples (32)
| Lab | Location | Arsenic certification | Public samples | Cert. expiry |
|---|---|---|---|---|
| ACZ Laboratories, Inc. | Steamboat Springs, CO | Named on the official list | Public samples: yes (per state) | 08/24/2027 |
| ALS Environmental - Kelso | Kelso, WA | Named on the official list | Public samples: yes (per state) | 07/08/2027 |
| AmTest Laboratories | Renton, WA | Named on the official list | Public samples: yes (per state) | 07/25/2027 |
| Analytical Resources, LLC | Tukwila, WA | Named on the official list | Public samples: yes (per state) | 06/30/2027 |
| Anatek Labs, Inc - Moscow | Moscow, ID | Named on the official list | Public samples: yes (per state) | 03/20/2027 |
| Anatek Labs, Inc - Spokane | Spokane, WA | Named on the official list | Public samples: yes (per state) | 11/15/2027 |
| Apex Laboratories, LLC | Tigard, OR | Named on the official list | Public samples: yes (per state) | 10/31/2027 |
| Brooks Applied Labs, LLC | Seattle, WA | Named on the official list | Public samples: yes (per state) | 05/15/2027 |
| BSK Associates | Fresno, CA | Named on the official list | Public samples: yes (per state) | 03/10/2027 |
| Columbia Laboratories, Inc. | Portland, OR | Named on the official list | Public samples: yes (per state) | 09/02/2027 |
| Continental Water Laboratory | Sacramento, CA | Named on the official list | Public samples: yes (per state) | 05/22/2027 |
| Energy Laboratories, Inc.-Billings, Mt | Billings, MT | Named on the official list | Public samples: yes (per state) | 12/05/2027 |
| Energy Northwest Environmental Services Lab | Richland, WA | Named on the official list | Public samples: yes (per state) | 04/11/2027 |
| Eurofins Lancaster Laboratories Environmental Testing, LLC | Lancaster, PA | Named on the official list | Public samples: yes (per state) | 04/11/2027 |
| Eurofins Pomona | Pomona, CA | Named on the official list | Public samples: yes (per state) | 03/13/2027 |
| Eurofins South Bend | South Bend, IN | Named on the official list | Public samples: yes (per state) | 01/01/2027 |
| Everett Environmental Laboratory | Everett, WA | Named on the official list | Public samples: yes (per state) | 04/21/2027 |
| Exact Scientific Services, Inc. | Ferndale, WA | Named on the official list | Public samples: yes (per state) | 08/20/2027 |
| Friedman & Bruya, Inc. | Seattle, WA | Named on the official list | Public samples: yes (per state) | 01/09/2027 |
| IEH Analytical Laboratories | Seattle, WA | Named on the official list | Public samples: yes (per state) | 06/17/2027 |
| LabTest | Yakima, WA | Named on the official list | Public samples: yes (per state) | 07/13/2027 |
| Matrix Sciences International Inc. dba KTL | Pasco, WA | Named on the official list | Public samples: yes (per state) | 09/02/2027 |
| OnSite Environmental, Inc. | Redmond, WA | Named on the official list | Public samples: yes (per state) | 07/26/2027 |
| Pace Analytical National Center for Testing & Innovation TN | Mt. Juliet, TN | Named on the official list | Public samples: yes (per state) | 08/19/2027 |
| Pace Analytical Services, LLC - Mansfield, MA (320 Forbes) | Mansfield, MA | Named on the official list | Public samples: yes (per state) | 11/07/2027 |
| Pace Analytical Services, LLC - Minneapolis MN | Minneapolis, MN | Named on the official list | Public samples: yes (per state) | 02/18/2027 |
| Precision Analytical Laboratories, LLC | Everett, WA | Named on the official list | Public samples: yes (per state) | 09/25/2027 |
| RJ Lee Group, Inc. - PA | Monroeville, PA | Named on the official list | Public samples: yes (per state) | 12/30/2026 |
| RJ Lee Group, Inc. Columbia Basin Analytical Laboratories | Pasco, WA | Named on the official list | Public samples: yes (per state) | 07/13/2027 |
| Rose City Laboratories, LLC | Portland, OR | Named on the official list | Public samples: yes (per state) | 06/14/2027 |
| SGS North America, Inc. | Clovis, CA | Named on the official list | Public samples: yes (per state) | 11/18/2027 |
| Water Management Laboratories, Inc. | Tacoma, WA | Named on the official list | Public samples: yes (per state) | 01/31/2027 |
Other labs on the list (1)
| Lab | Location | Arsenic certification | Public samples | Cert. expiry |
|---|---|---|---|---|
| DCI Laboratory | Nashville, TN | Named on the official list | Not marked as taking public samples | 10/22/2027 |
How the Washington list marks public samples (whole list). Yes/no from Ecology's 'Search labs that accept public samples' list, where the label is 'Accepts Commercial/Public Samples'. That is broader than 'homeowner' and includes some utility labs, so call before you send a sample.
Before you send a sample, call the lab to confirm it is currently certified for the exact test and method, that it accepts samples from homeowners, and how to collect and ship them. Status can change between list updates.
Why test for arsenic in Washington
Arsenic is invisible, tasteless and mostly natural, and it comes in two forms that respond very differently to treatment. Read our arsenic explainer.
Washington guidance that mentions arsenic:
- Coliform bacteria and nitrate every year. If nitrate is 5 mg/L or higher, the state says you may want to re-test in six months. It also suggests testing arsenic at least twice while you own the home, once in summer and once in winter. [1]
USGS estimates that the most private-well users with arsenic above 10 µg/L, EPA's limit for public water, live in Yakima County, Snohomish County and Benton County (about 6,940 people in Yakima County, 2010 base year). USGS describes this kind of estimate as useful "for broad screening of the population at risk", so it says nothing certain about any one well. [2]
Show the numbers
| Item | Value | Note |
|---|---|---|
| Yakima County | 6,940 people (2010 base year) | |
| Snohomish County | 6,178 people (2010 base year) | |
| Benton County | 5,218 people (2010 base year) | |
| Clark County | 4,768 people (2010 base year) | |
| Grant County | 4,097 people (2010 base year) | |
| Spokane County | 3,271 people (2010 base year) |
USGS model estimate for broad screening, not a measurement of any well. Only a test tells you about your own well. Source: USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017), accessed 2026-11-01.
About 1,023,853 people in Washington used private wells in 2015, by the USGS estimate of people on domestic self-supplied water. [3] Federal limits are written for public water systems, not private wells, so testing is up to the owner.
For tests that depend on your home (farms nearby, old plumbing, a new baby), use the which-tests checklist. When results arrive, check your numbers against EPA's limits. State guidance, county data and every lab: Washington.
Other tests in Washington
- Washington State Department of Health, Testing your water
- USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017)
- USGS, Estimated use of water in the United States, county-level data for 2015 (Dieter et al., ver. 2.0, 2018)
- WA Ecology - Environmental Laboratories Accredited for Drinking Water Analyses (with scopes) (official list)
WA Ecology - Environmental Laboratories Accredited for Drinking Water Analyses (with scopes).
Official source