Well water in Aroostook County
Water in Aroostook County is spread out, like everything else. Town systems cover the centers of Presque Isle, Caribou, and Houlton, and past the last hydrant nearly every farmhouse, homestead, and camp runs on its own well. Two County facts should shape what owners do about that. First, this is Maine's farm belt, potato country above all, and nitrate, which moves into groundwater from fertilizer and septic sources, is on Maine CDC's yearly test list with a 10 mg/L guideline (Maine CDC testing guidance; guideline values at the Maine Tracking Network).
Second, The County is under-tested. The Maine Tracking Network collects well-testing rates by county from state survey data (Maine Tracking Network), and Aroostook is one of four counties the network's partners singled out for campaigns to raise testing rates, alongside Franklin, Hancock and Washington (Maine Tracking Network). Low testing does not mean low risk; it means the local picture is mostly blank, in a state where about one domestic well in 10 exceeds the federal arsenic standard.
Two kinds of County wells
Aroostook geology splits its wells. The Maine Geological Survey has mapped significant sand and gravel aquifers here, including in the Presque Isle quadrangle (MGS aquifer map): productive coarse deposits whose open structure also lets surface contaminants like nitrate leach toward the water table, a real consideration beside working fields. Drilled bedrock wells, the other type, carry more of the naturally occurring arsenic, uranium, and radon risk. The yearly bacteria-and-nitrate habit plus the three-to-five-year bedrock panel covers both cases; the testing checklist lays out the schedule.
Getting from sample to fix, at County distances
Mail-order kits from the state lab in Augusta work the same from Fort Fairfield as from Falmouth, and the testing page covers panels, certified labs, and costs. When a result needs equipment, a coliform hit points to UV and bacteria treatment, staining points to iron and manganese filtration, and high nitrate or arsenic results get their own designs. A free quote comes back from an independent professional who actually covers this territory. Every region is on the service areas page.
One more farm-country note: PFAS. Maine set an interim standard of 20 ng/L for the sum of six PFAS compounds in private wells, and Maine DEP offers free PFAS testing for wells near known sludge and septage spreading sites, reachable at (207) 287-7688, with funded filtration where contamination is linked to spreading (Maine CDC and DEP). If your land or a neighbor's has a spreading history, that call is free and worth making; background is on the PFAS treatment page.
Towns served in this region: Presque Isle, Caribou, Houlton, Fort Fairfield, Mars Hill, and Limestone.