Tap Water Results

Maine PFAS results from EPA's final data

Report published Nov 14, 2026 · EPA UCMR 5 final data file of Oct 15, 2026 (samples collected 2023–2025) · Method · National results →

2 Maine water systems serving 22,328 people had PFAS above a 2024 federal limit in EPA's final round of nationwide PFAS testing: 5% of the 39 Maine systems tested, compared with 11% nationally.

39
systems tested (serving 533,313 people)
9
had at least one PFAS detected
2
had an average above a federal limit
22,328
people served by those systems

Highest PFOA or PFOS averages in Maine

  1. Yarmouth Water District Yarmouth · PFOA
    8.15 ppt
  2. Sanford Water District Sanford · PFOA
    6.2 ppt
  3. Kennebec Water District Waterville · PFOA
    3.98 ppt
  4. Houlton Water Company Houlton · PFOS
    2.4 ppt
  5. Lisbon Water Department Lisbon · PFOA
    2.05 ppt
The 5 Maine systems with the highest PFOA or PFOS entry-point average (whichever is higher) in EPA's 2023–2025 testing, in parts per trillion.
Chart data as a table
Systemppt
Yarmouth Water District · Yarmouth · PFOA8.15
Sanford Water District · Sanford · PFOA6.2
Kennebec Water District · Waterville · PFOA3.98
Houlton Water Company · Houlton · PFOS2.4
Lisbon Water Department · Lisbon · PFOA2.05

Largest systems above a limit

#SystemPeople servedAbove the limit forPFOA avgPFOS avg
1Sanford Water District
Sanford
Above: PFOA, PFOS
14,328PFOA, PFOS6.2 ppt6.15 ppt
2Yarmouth Water District
Yarmouth
Above: PFOA
8,000PFOA8.15 ppt–

Which limits were exceeded

PFASFederal limitSystems above itPeople served
PFOA
22,328 people
4 ppt222,328
PFOS
14,328 people
4 ppt114,328
PFHxS10 ppt00
PFNA10 ppt00
GenX (HFPO-DA)10 ppt00
Hazard Index100

"–" in the table above means not detected. A system can be above more than one limit. EPA proposed in May 2026 to rescind the PFHxS, PFNA, GenX and Hazard Index limits. That proposal is not final.

Maine has its own PFAS rules. Interim standard (alone or combined) per 2021 law. It stays in effect until 2027-04-26, when federal MCLs adopted by reference in 10-144 CMR Ch. 231 take over. Details. This report compares results with the federal limits only.

Data and how to cite it

Suggested citation:

Tap Water Results, "Maine PFAS results from EPA's final UCMR 5 data" (published Nov 14, 2026, EPA data file of Oct 15, 2026). https://tapwaterresults.com/pfas/maine/

You're welcome to quote and republish these figures with a link back. Questions from reporters: see contact.

Method

For each system we average each entry point's UCMR 5 results (non-detects count as zero, complete sets of samples only) and compare the highest entry-point average with the 2024 federal limit, using EPA's rounding. This is how EPA compares UCMR 5 results to the limits in its own data summary, and our national counts match EPA's published table within 2% (how we check). Results are monitoring data from 2023–2025, not compliance determinations, and treatment installed since then is not reflected. Full method.

Questions

How many Maine water systems have PFAS above the limit?

2 of the 39 Maine community water systems EPA tested in 2023–2025 (5%) had at least one entry-point average above a 2024 federal PFAS limit. They serve 22,328 people. Nationally the share is 11%.

Are these systems violating the law?

Not yet. Systems have until 2029 to meet the 2024 limits, and EPA has proposed moving the PFOA and PFOS deadline to 2031 and rescinding the other limits. EPA's UCMR 5 results are monitoring data and do not determine compliance.

Which systems were tested?

EPA's UCMR 5 tested every community water system serving more than 3,300 people and a representative sample of smaller ones. Systems that were not tested have no federal result, which is not the same as having no PFAS.

All Maine water systems → · National results → · PFAS results for every state →

Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.