Washington County, Maine: drinking water report. Washington County sits in Maine's far northeastern corner, covering communities from Calais and Eastport…
Washington County sits in Maine's far northeastern corner, covering communities from Calais and Eastport along the Canadian border to Machias and Lubec on the coast. Most residents rely on private wells or small municipal systems drawing from groundwater aquifers and surface water sources like the St. Croix River and numerous coastal watersheds. The rural character of this sparsely populated county means centralized water treatment reaches only a fraction of homes, leaving many households responsible for their own water quality monitoring.
Maine's bedrock geology creates specific concerns for Washington County well users. Arsenic appears in groundwater throughout the state, particularly in crystalline bedrock formations common to eastern Maine. The Maine Geological Survey has documented elevated arsenic levels in wells across Washington County, with concentrations sometimes exceeding the EPA's 10 parts per billion standard. This naturally occurring contamination requires testing that many private well owners skip, since no regulatory body mandates regular monitoring for residential wells.
The coastal portions of Washington County face saltwater intrusion challenges that climate change and sea level rise will likely worsen. Wells near Eastport, Lubec, and other Down East communities can show elevated sodium and chloride levels when tidal influences or heavy pumping draw seawater into freshwater aquifers. Meanwhile, the agricultural and blueberry farming operations that anchor the county's rural economy introduce nitrate and pesticide pathways into groundwater, though concentrations typically remain lower than in more intensively farmed regions.
PFAS contamination patterns in Maine have centered on industrial and military sites, but Washington County's distance from major contamination sources does not guarantee clean water. The state's 2021-2023 PFAS sampling detected these persistent chemicals in unexpected locations, and small water systems serving places like Calais have faced pressure to test. Many of the county's older homes also contend with lead risks from plumbing installed before corrosion control became standard practice, particularly in buildings constructed before 1986.
If you rely on a private well, test for arsenic, bacteria, nitrates, and basic water chemistry at least every three years. Municipal system users should request their annual Consumer Confidence Report and consider additional testing if their home has older plumbing. Check your water for current data on detected contaminants, review our water filter guide for treatment options matching specific concerns, get your detailed report showing what's been found in your area, or visit the Maine state page for statewide context on arsenic and PFAS issues.