About 55% of the county's 51,113 residents. Rank 10 of 16 in Maine.
95% range 5,876 to 8,786 private-well users (2010 base year). Rank 6 of 16 in Maine.
Highest potential (average indoor radon may be greater than 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 Somerset 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 7,247 people using private wells in Somerset County had arsenic above 10 µg/L, EPA's limit for public water (2010 base year; 95% range 5,876 to 8,786). 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 Somerset County in Zone 1: highest potential (average indoor radon may be greater than 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) | |
| Somerset County (this county) | 7,247 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.
PFAS in public water near Somerset County (public supply, not your well)
This is public water data, not your well. A private well draws its own groundwater, which can have more or less PFAS than the public supply nearby. Only a test of your well tells you.
Under EPA’s fifth Unregulated Contaminant Monitoring Rule (UCMR 5), public water systems sampled their water for 29 PFAS between Jan 3, 2023 and Jun 17, 2026. 3 public systems that serve ZIP codes mainly in Somerset County reported results. 1 of them had at least one sample with PFOA or PFOS at or above 4.0 ng/L, and 1 had at least one of the 29 PFAS measured at or above its reporting level.
| Public water system | System ID | Highest PFOA (ng/L) | Highest PFOS (ng/L) |
|---|---|---|---|
| Kennebec Water District | ME0090750 | 6.4 |
4.0 ng/L (parts per trillion) is both EPA’s UCMR 5 reporting level for PFOA and PFOS and the number in EPA’s 2024 limit for public water. That limit is judged on a running annual average, so one sample at that level is not a violation. EPA proposed changes to its PFAS rules in May 2026: see PFAS in well water for the current status and who should test a well. To test your own well, find a lab certified for PFAS.
Method: a system counts for this county when it reports serving a ZIP code whose largest land part is in this county, so a system serving several counties counts in each. Source: U.S. EPA, UCMR 5 occurrence data (by state), file dated Oct 15, 2026; downloaded Nov 1, 2026.
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 Somerset County
Loan test (FHA, VA, USDA) in Somerset 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 Somerset County
Maine Laboratories, LLC (PFAS Only)
Norridgewock, MEHomeowner samples: yes (lab’s website)Maine Laboratories LLC, dba PFAS Laboratories
25 Main St, Norridgewock, MEPublic samples: yes (per state)Testing by mail from Somerset 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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