About 64% of the county's 31,625 residents. Rank 12 of 16 in Maine.
95% range 2,014 to 3,820 private-well users (2010 base year). Rank 11 of 16 in Maine.
Moderate potential (average indoor radon may be between 2 and 4 pCi/L). EPA says the map should not be used to decide whether an individual home needs testing.
Labs with an address in this county, from the official state lists on this site, matched by ZIP code.
What to test for in Washington County
Private wells are not regulated like public water: EPA advises owners to test their well every year for total coliform bacteria, nitrates, total dissolved solids and pH. Your state's own schedule:
- Every year: coliform bacteria, E. coli, nitrate and nitrite. Every three to five years: arsenic, chloride, copper, fluoride, hardness, iron, lead, magnesium, manganese, pH, radon, sodium and uranium. source
Arsenic. USGS estimates that about 2,816 people using private wells in Washington County had arsenic above 10 µg/L, EPA's limit for public water (2010 base year; 95% range 2,014 to 3,820). 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. Arsenic has no taste or smell: test for it by name.
Radon. EPA puts Washington County in Zone 2: moderate potential (average indoor radon may be between 2 and 4 pCi/L). That map is about radon in indoor air, and EPA says it should not be used to decide whether an individual home needs testing. If radon is found in your air and you have a well, EPA suggests testing the water too: see radon in well water.
For anything specific to your home (farms nearby, old plumbing, a new baby, a smell or stain), use the which-tests checklist. When the results arrive, check your numbers against EPA's limits.
Show the numbers
| Item | Value | Note |
|---|---|---|
| Penobscot County | 18,708 people (2010 base year) | |
| Kennebec County | 15,277 people (2010 base year) | |
| York County | 10,409 people (2010 base year) | |
| Androscoggin County | 9,698 people (2010 base year) | |
| Aroostook County | 9,500 people (2010 base year) | |
| Washington County (this county) | 2,816 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.
Testing programs and help in Maine
- Maine CDC gives free technical help by phone, and low-income residents can fill out a form to get more information about testing or a test kit. source
Buying a home with a well in Washington County
Loan test (FHA, VA, USDA) in Washington County, ME
- VA. Test results are valid for 90 days from the date the local health authority certifies them, unless the local authority says otherwise. VA’s chapter names no list of contaminants: the water must meet the local health authority’s requirements, or EPA guidelines where it has none. Your lender may ask for specific tests.
- FHA. A well test is required in the situations FHA’s handbook lists, among others, and the report may not be more than 180 days old at disbursement.
- USDA. Guaranteed loans need a water quality test for a private well, done by the local health authority or a state-certified lab, and no more than 180 days old at closing.
Here:
- Maine Health and Environmental Testing Laboratory web shop: Well Evaluation / New Well / Residential Home Sales test, $127 (checked 1 Nov 2026) source
Lenders can ask for more (extra tests, a particular lab, who takes the sample): ask your lender before you book. Federal rules as read on Nov 3, 2026 source 1 source 2 source 3. Full comparison: VA, FHA and USDA well water test requirements. Loan test kits sold by mail, with price and days to results: kits compared.
State-certified labs in Washington County
None of the labs on our Maine list has an address in Washington County. Labs elsewhere in the state may take samples by mail or courier: ask the lab, and check the hold time for bacteria before you send one.
Testing by mail from Washington County. Maine Health and Environmental Testing Laboratory web shop publishes these prices: Basic Safety Test $42; Well Evaluation / New Well / Residential Home Sales test $127; Lead, first draw $32 (checked 1 Nov 2026) source. All Maine state-lab prices and how to get a kit.
Labs on the Maine list whose own websites say they take homeowner samples: ClearWater Laboratory (A Division of Acheron Engineering) (Newport), Health and Environmental Testing Laboratory (Augusta), Maine Coast Laboratory (DBA Water Quality & Compliance Services Inc.) (Wiscasset), Maine Laboratories, LLC (PFAS Only) (Norridgewock), Mi'Kmaq Environmental Laboratory (Bacteria only) (Presque Isle), NELAnalytical (Previously Northeast Laboratory Services) (Winslow), Nelson Analytical Lab (Kennebunk), Nova Analytic Labs (DBA Nova EnviroLabs – PFAS Only) (Portland). Use Check my ZIP to sort labs by distance.
See all Maine labs in the finder and filter by the test you need and by labs that take homeowner samples.
- USGS, Estimated use of water in the United States, county-level data for 2015 (Dieter et al., ver. 2.0, 2018)
- USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017)
- U.S. EPA, Map of Radon Zones, county list (EPA 402/A-16/001)
- U.S. Census Bureau, 2020 ZCTA to county relationship file (lab ZIP codes to counties)
- Maine In-State Commercial Drinking Water Labs (Last updated 5/16/2026)
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