Remove PFAS from Maine Drinking Water

Maine's PFAS problem took a route almost unique in the country. For decades, treated sewage sludge and biosolids were spread across farmland as low-cost fertilizer, and that practice quietly seeded the soil and shallow groundwater with PFAS. The result is a pattern of agricultural and private-well contamination unusually tied to farm fields, with Fairfield emerging as its most familiar name. The scope was alarming enough that Maine became the first state in the nation to prohibit spreading PFAS-tainted sludge, a ban it enacted in 2022.

What was found around Fairfield set off a statewide Maine DEP effort to examine soil and groundwater at properties licensed to land-apply sludge or septage before 2019. Hundreds of those locations were sorted into priority tiers for sampling, an approach documented by the Maine DEP, the Department of Agriculture, Conservation and Forestry, and Inside Climate News. Since so many of the affected parcels are working farms and rural homesteads drawing from private wells, the contamination often behaves in a highly local way, differing from one field or one property line to the next. That pattern sets Maine apart from states whose PFAS troubles trace to a single factory outfall or airfield. Here the source was spread deliberately and thinly across countless acres of soil, so the risk maps onto land-use history rather than distance from one facility, and a property's past as a hay field or a spreading site can matter more than its ZIP code.

Maine's interim standard alongside the federal limits

Maine adopted an interim drinking-water standard capping six PFAS at 20 ppt combined: PFOA, PFOS, PFHxS, PFNA, PFHpA, and PFDA. It paired that with risk-based soil screening values to steer the land investigation. Layered on top is the 2024 federal EPA rule, which enforces 4 parts per trillion each for PFOA and PFOS and 10 ppt each for PFNA, PFHxS, and the GenX chemicals. Where the state and federal frameworks cover the same ground, a system has to satisfy whichever protection governs.

Testing in a high-risk state

Living near a former sludge or septage application site, or drawing from any private well in an affected district, makes a certified laboratory test essential; use EPA Method 537.1 or 533. Public-system customers can pull their utility's PFAS results or Consumer Confidence Report, but well owners have to commission testing on their own. Maine has operated one of the most aggressive state investigation programs anywhere, and residents near tiered application sites may qualify for state-supported sampling, so it pays to consult current DEP guidance before booking a private lab. And because contamination on old fields tends to be patchy, testing your own well rather than borrowing a neighbor's result is the surest way to gauge your real exposure.

Three removal approaches

Granular activated carbon (GAC): a sturdy whole-house method that adsorbs PFAS, a natural fit for Maine's many private wells. Anion exchange resin: zeroes in on charged PFAS and helps with the short-chain varieties. Reverse osmosis (RO): a membrane barrier that strips a wide range of PFAS at the drinking tap. A whole-house GAC or anion unit shields the entire home, while an under-sink RO adds a focused last line of defense for the water you consume. Given how elevated the risk runs in some Maine communities, coupling whole-house treatment with point-of-use RO is a sensible, common plan. On a rural Maine homestead the whole-house stage also protects the water used for gardens, livestock troughs, and outdoor spigots, while the kitchen RO concentrates the most stringent treatment where the family actually drinks.

Recommended systems

Read our PFAS water filter removal guide to match a system to your results.