Well water in Aroostook County, ME: what to know and what to test for

Bottom line

About9,500people on private wells may have arsenic above the drinking water limit of 10 micrograms per liter (likely 7,700 to 11,400).

Among the higher estimated numbers of affected well users in Maine.

Indoor radon potential: High

Find an accredited lab

How 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)

Source: Maine Department of Health and Human Services, 10-144 CMR Chapter 257, Health and Environmental Testing Laboratory Fee Schedule

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

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.

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.

Aroostook Public Health District

Stacy Boucher, MSHS, Aroostook District Public Health Liaison

Tribal Public Health District

Tribal Public Health District

Joshua Toner, Tribal Public Health District Liaison

207-532-4273 Ext: 227

Towns in Aroostook County

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 literU.S. Geological Survey, 2017
EPA Map of Radon ZonesU.S. Environmental Protection Agency, 1993
10-144 CMR Chapter 257, Health and Environmental Testing Laboratory Fee ScheduleMaine Department of Health and Human Services, 2020
22 MRS §2660-T, Uniform private well testing recommendationsMaine Legislature, 2025
Maine In-State Commercial Drinking Water LabsMaine Drinking Water Program, 2026
Accredited Laboratories in MaineMaine Center for Disease Control and Prevention, 2026
All laboratories accredited by MaineMaine Drinking Water Program, 2026
Maine public health districtsMaine Center for Disease Control and Prevention
2026 Gazetteer file for Maine county subdivisionsU.S. Census Bureau, 2026
30-A MRS §2001, municipalityMaine Legislature, 1989
Private Well WaterMaine Center for Disease Control and Prevention