Maine tightened its drinking water standards this year — and left more than half the state’s households outside the rule.
Roughly 55% of Maine residents drink from a private well. Not one of those wells is covered by the PFAS standard Maine adopted in December.
The new rule cuts the allowable amount of PFOA and PFOS in public drinking water to 4 parts per trillion each — about four drops spread across twenty Olympic swimming pools — with a combined limit of 10 ppt for three other PFAS compounds. Public water systems begin monitoring under the rule in 2027, with initial enforcement in 2028.
Private wells get none of that. No required monitoring, no reporting, no letter in the mail when something shows up. What you know about your own water is exactly what you have paid to find out.
That gap matters more than it used to. In one Maine sampling effort covering about 100 private wells, close to 7 in 10 had detectable PFAS and roughly 1 in 6 came back above the state’s current standard. Across the border, New Hampshire estimates about 40% of residents rely on private wells with no mandatory testing, and state sampling has found PFAS above New Hampshire’s standard in a meaningful share of the wells tested.
What the New Rule Actually Changes
PFAS — per- and polyfluoroalkyl substances, the “forever chemicals” — do not break down in the environment and accumulate in the body over time. PFOA and PFOS are the two most studied and the two Maine is regulating most tightly.
The number to pay attention to is not the health science. It is the moving regulatory floor. Maine’s earlier interim standard was 20 parts per trillion for six PFAS compounds combined; the Maine DEP still uses that 20 ppt figure in its ongoing statewide investigation. The new drinking water rule sets 4 ppt for PFOA and PFOS individually. At the federal level, the EPA proposed changes to its own PFAS drinking water rules in May 2026, with a public hearing this month and a comment period still open. Maine’s adopted amendments are not affected by the federal proposal.
For a well owner, the practical takeaway is simple: a result that looked clean under a 20 ppt yardstick may not look clean under a 4 ppt one. And if your last PFAS test used a higher reporting limit, a “non-detect” may only mean the lab was not looking that low. Ask what the reporting limit was before you assume you are fine.
What Homeowners Should Do
Test for PFAS at least once. If you have never tested, that first result is the whole point — it either closes the question or opens it. Retest every few years, and sooner if your well sits near a known source: former sludge or septage spreading fields, fire training areas, landfills, or manufacturing sites.
Keep up the annual basics. Total coliform bacteria, E. coli, and nitrate/nitrite should be tested every year. Summer is a sensible time to do it. Research out of the University of New Hampshire found bacteria levels in private wells run highest during warm stretches — meaning a July sample is more likely to reveal a real problem than a February one.
Cover the geology on a longer cycle. Arsenic, uranium, and radon in water are naturally occurring across much of Maine and New Hampshire bedrock and warrant testing every three to five years.
Know what a real estate panel does and does not include. The FHA/VA basic safety panel required at many closings covers bacteria, nitrate, nitrite, and lead. It does not include PFAS. Buyers are asking about PFAS more often than they were two years ago, and sellers with a clean, recent result have something concrete to hand over instead of a shrug.
What Chanalytical Tests For
Chanalytical’s analyte menu is built around the contaminants that actually turn up in Northeast wells: arsenic, uranium, radon in water, PFAS including PFOA and PFOS, lead, nitrate and nitrite, total coliform and E. coli, metals, and hardness. Panels run from the FHA/VA Basic Safety Test up through a 20-analyte Comprehensive panel, with radon and PFAS available as additions or standalone tests.
For Home Inspectors
Water results are one of the few line items that can hold up a closing. Working with a local lab shortens that timeline: samples processed in Gorham, most panels reported the next business day, and report-ready PDFs you can attach directly to your inspection file. Nine drop-off locations across the state — Gorham, Scarborough, Steep Falls, New Gloucester, Auburn, Augusta, and Hermon — mean the sample does not have to ride along for a day before it reaches a lab.
For Water Treatment Companies
PFAS treatment is where third-party testing earns its keep. A baseline result before you quote defines the problem. A post-installation sample confirms the system is doing what you told the customer it would do. And periodic follow-up testing catches media breakthrough before the homeowner does — carbon and reverse osmosis systems are not set-and-forget, and rebate and verification programs across the region increasingly require documented post-treatment results. Independent lab data protects the installer as much as the customer.
Why Trust Chanalytical
Chanalytical is an independent, Maine-based laboratory in Gorham, run by scientists who work on this state’s water every day and know which contaminants belong to which bedrock. Because the lab has no stake in selling treatment equipment, the number on the report is just the number — no upsell attached to it. Results arrive as plain-English PDFs, most panels within one business day, and when you call (207) 747-1815 a person picks up.
Get Your Well Tested
Maine’s regulators are tightening the standard for everyone else’s water. Yours is still your call.
Order a panel, find your nearest drop-off location, or set up a partner account for your inspection or treatment business at chanalytical.com, or call (207) 747-1815. Maine-based lab, next-business-day results on most panels, and reports built for the deadlines you are actually working against.