Well Water in Lincoln County, Maine

Lincoln County · Population ~35,000 (county); higher in summer · Aquifer: Bedrock / Coastal Surficial

Lincoln County on Maine's midcoast is a mix of year-round communities and seasonal coastal towns. Nearly all residents are on private wells, and the county's geology — granitic bedrock interspersed with metamorphic formations — produces elevated arsenic, radon, and uranium in many wells. The seasonal population surge adds stress to coastal aquifers already at risk of saltwater intrusion.

Arsenic in the Midcoast

Lincoln County's bedrock geology is a significant source of arsenic in well water. The granitic formations that underlie much of the county contain arsenopyrite and other arsenic-bearing minerals that dissolve into groundwater over time.

Testing data from the Maine Geological Survey shows that arsenic exceedances in Lincoln County are consistent with the statewide pattern: roughly 1 in 10 bedrock wells exceeds the EPA's 10 µg/L standard.

Free arsenic testing is available through the Maine CDC. See our arsenic guide and testing guide.

Radon and Uranium

Like much of coastal Maine, Lincoln County has elevated radon in both indoor air and well water. The same granitic bedrock that produces arsenic also produces radon (from the radioactive decay of uranium in the rock).

If your home has been tested for indoor air radon and the levels are elevated, your well water likely contains dissolved radon too. Water treatment for radon involves either aeration (bubbling air through the water to release radon gas, then venting it outside) or granular activated carbon (which adsorbs radon but creates a mildly radioactive filter that needs proper disposal).

Seasonal Homes and Stale Water

Many Lincoln County properties are seasonal — used heavily in summer and closed up for winter. This creates a specific water quality concern: stale water sitting in wells and plumbing for months can develop elevated bacteria counts and increased concentrations of dissolved metals.

If you're opening a seasonal property after months of disuse, run the water for 15-20 minutes before using it to flush the plumbing and wellbore. Consider testing after the first flush to establish a baseline before the season begins.

Testing Recommendations

Test for arsenic (free), radon, uranium, bacteria, nitrate, and pH. Coastal properties should add chloride and sodium for saltwater intrusion screening. Seasonal properties should test at the start of each season.

See our testing guide for labs and programs.

Every well is different. Two wells on the same street can produce completely different water. The data on this page reflects documented conditions in the Lincoln County area, but the only way to know what's in your water is to test it.

Sources

  • Maine Geological Survey — Arsenic in Groundwater
  • Maine CDC — Radon in Well Water
  • USGS — Radon and Uranium in New England Groundwater
  • Maine CDC — Seasonal Well Opening Guidelines