Health and Environmental Testing Laboratory
Augusta
Accredited for
- Bacteria and nitrate
- Metals (arsenic, lead, uranium)
- PFAS
Call to request a private well test kit and price.
Well water in Knox County, ME: what to know and what to test for
Bottom line
About1,000people on private wells may have arsenic above the drinking water limit of 10 micrograms per liter (likely 700 to 1,400).
Among the lower estimates in Maine.
Indoor radon potential: Moderate
Maine CDC recommends testing every year for bacteria and nitrates, and every 3 to 5 years for arsenic, uranium, radon, and the other tests on its list.
Find an accredited labHow to read these numbers
USGS estimate based on 2010 population, published 2017.
Maine advises well owners to compare their results to this limit.
Larger counties have more well users, so higher counts don't mean any one well is more likely to be affected.
EPA zone for indoor air. It doesn't measure your well water.
What to test for
Maine's uniform recommended tests for private wells
10-144 CMR chapter 257 lists these tests for residential private wells. RES1 is the uniform testing recommendation compliant post-1988. The rule adds first draw lead for the package it calls the uniform testing recommendation compliant pre-1988. It does not define pre-1988 by home or plumbing age, and it does not say how often to test.
- coliform bacteria & E. coli (pos/neg)
- radon water
- nitrate
- nitrite
- fluoride
- chloride
- sodium
- hardness
- copper
- iron
- pH
- manganese
- uranium
- lead
- arsenic
- magnesium
- first draw lead (uniform testing recommendation compliant pre-1988)
How often to test (Maine CDC)
| Test | How often |
|---|---|
| Coliform bacteria, E. coli, and nitrates and nitrites | Every year |
| Arsenic, chloride, copper, fluoride, hardness, iron, lead, magnesium, manganese, pH, radon, sodium, and uranium | Every 3 to 5 years |
Other times to test
- If you have never tested your well, do a comprehensive or standard test for everything listed above.
- If you are expecting a baby
- Your water changes in smell, taste, and color
- Your well runs dry and comes back
- When buying a new home
- After installing a water treatment system or replacing parts of your treatment system
- After any work is done on your well
Source: Maine Center for Disease Control and Prevention, Testing your well water
Maine law (22 MRS §2660-T) also names PFAS among recommended private well tests.
Source: Maine Legislature, 22 MRS §2660-T, Uniform private well testing recommendations
Questions about what to test for or what your results mean? Contact the Maine CDC Toxicology Team at (207) 287-4311 or [email protected].
Source: Maine Center for Disease Control and Prevention, Private Well Water
Where to test
Accredited labs in Maine. Most accept mail-in samples.
Standard well tests
Katahdin Analytical Services
Scarborough
SGS Scarborough
Accredited for
- Bacteria and nitrate
- Metals (arsenic, lead, uranium)
- PFAS
Call to request a private well test kit and price.
NELAnalytical
Winslow
Previously Northeast Laboratory Services
Accredited for
- Bacteria and nitrate
- Metals (arsenic, lead, uranium)
Call to request a private well test kit and price.
Nelson Analytical Lab
Kennebunk
Accredited for
- Bacteria and nitrate
- Metals (arsenic, lead, uranium)
Call to request a private well test kit and price.
Bacteria tests only
ClearWater Laboratory
Newport
A Division of Acheron Engineering
Accredited for
- Bacteria and nitrate
Call to request a private well test kit and price.
Eurofins Auburn
Auburn
Previously A&L
Accredited for
- Bacteria and nitrate
Call to request a private well test kit and price.
Eurofins Portland ME
Portland
Bacteria only
Accredited for
- Bacteria and nitrate
Call to request a private well test kit and price.
Maine Coast Laboratory
Wiscasset
DBA Water Quality & Compliance Services Inc.
Accredited for
- Bacteria and nitrate
Call to request a private well test kit and price.
Mi'Kmaq Environmental Laboratory
Presque Isle
Bacteria only
Accredited for
- Bacteria and nitrate
Call to request a private well test kit and price.
PFAS tests only
Bigelow Laboratory for Ocean Sciences
East Boothbay
PFAS Only
Accredited for
- PFAS
Call to request a private well test kit and price.
Maine Laboratories, LLC
Norridgewock
PFAS Only
Accredited for
- PFAS
Call to request a private well test kit and price.
Nova Analytic Labs
Portland
DBA Nova EnviroLabs – PFAS Only
Accredited for
- PFAS
Call to request a private well test kit and price.
Labs are accredited test by test. Call to confirm a lab can run every test you need.
Lab list current as of May 16, 2026, from the Maine Drinking Water Program.
Public health district
Your public health district is the local contact for private well questions.
Midcoast Public Health District
Lindsey O'Hara, Midcoast District Public Health Liaison (Interim)
Towns in Knox County
- Appleton
- Camden
- Cushing
- Friendship
- Hope
- Isle au Haut
- Matinicus Isle (plantation)
- North Haven
- Owls Head
- Rockland
- Rockport
- South Thomaston
- St. George
- Thomaston
- Union
- Vinalhaven
- Warren
- Washington
Unorganized territories in this county are served directly by Maine CDC.
Nearby counties
Sources
- Estimated county-level domestic well population with arsenic greater than 10 micrograms per liter
- EPA Map of Radon Zones
- 10-144 CMR Chapter 257, Health and Environmental Testing Laboratory Fee Schedule
- 22 MRS §2660-T, Uniform private well testing recommendations
- Maine In-State Commercial Drinking Water Labs
- Accredited Laboratories in Maine
- All laboratories accredited by Maine
- Maine public health districts
- 2026 Gazetteer file for Maine county subdivisions
- 30-A MRS §2001, municipality
- Private Well Water