Use a lab Maine certifies, or a mail-in kit. Across the state, the ones worth testing for are radon, uranium, arsenic and manganese, plus bacteria and nitrate every year.
About 630,000 people in Maine get their water from a private well, about 5 in 10 residents.
Maine doesn't run a statewide free testing program that we know of. Some county health departments still test wells or sell kits, so call yours first.
Maine CDC (Department of Health and Human Services), Drinking Water Program: private well testingThe state's list of labs certified for drinking water. Many sell bottles you pick up or get by mail, and their results count for a home sale or loan.
Labs certified by MaineOrder online, fill the bottles at your kitchen tap and get results by email in about a week. Full well tests run about $210 to $220.
Compare kits for MaineShare of tested wells over the limit, from lab tests the USGS, EPA and state agencies collected since 2000. Your own well needs its own test.
Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+
Lab results: Water Quality Portal (USGS and EPA)
The arsenic figure comes from a random sample of about 1,000 household wells. The public lab data for Maine put it at 67% of tested wells, but those wells were picked by research and monitoring programs, not at random.
5 counties have a full report with local test results and well depths.
No full report for that county yet. The statewide results above still apply, and so do the three ways to get tested.
| County | People on private wells | Share of residents | Typical well depth |
|---|---|---|---|
| York County | 94,758 | 45% | 280 ft |
| Cumberland County | 88,596 | 29% | 264 ft |
| Penobscot County | 64,066 | 42% | 200 ft |
| Kennebec County | 61,482 | 50% | 230 ft |
| Androscoggin County | 42,405 | 38% | 280 ft |
| Aroostook County | 40,213 | 60% | 162 ft |
| Hancock County | 37,979 | 68% | 225 ft |
| Oxford County | 35,217 | 61% | 324 ft |
| Somerset County | 28,288 | 56% | 240 ft |
| Waldo County | 25,567 | 65% | 200 ft |
| Lincoln County | 25,468 | 72% | 206 ft |
| Washington County | 20,788 | 67% | 200 ft |
| Knox County | 20,181 | 50% | 180 ft |
| Sagadahoc County | 18,026 | 49% | 216 ft |
| Franklin County | 17,026 | 58% | 255 ft |
| Piscataquis County | 9,743 | 58% | 185 ft |
Maine doesn't require routine testing of existing private wells. Keeping a well safe is up to the owner, so test for bacteria and nitrate every year.
Otherwise, use a lab certified by Maine for drinking water. The state's list is linked on this page.