How hard is the water in Washington County, ME?
1.2 grains per gallon
You do not need a softener here.
The median hardness measured in Washington County, ME is 20 mg/L as calcium carbonate, which is 1.2 gpg. That is soft on the USGS scale. It comes from 27 samples at 7 sites between 1990 and 2023, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 0.8 and 4 gpg. That spread crosses a decision line, so some homes here land on a different answer. A $10 test strip on your own tap settles it. Confidence in the county figure: medium (how it is measured).
What to do next
You can skip the softener. At 1.2 gpg the most a softener would fix is the odd water spot. If a salesperson in Washington County says otherwise, ask to see their reading in grains per gallon and compare it with this one. Because Washington County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on when a softener is not worth it.
From 0.6 to 16.2 gpg
The softest single sample on record in Washington County was 9.9 mg/L and the hardest 277 mg/L, a 28-fold gap. The top quarter of sites read above 4 gpg and the bottom quarter below 0.8 gpg. So even in a soft county, a handful of wells here produce water hard enough to scale a heater.
Wells 5 gpg, rivers and lakes 0.8 gpg
4 groundwater samples from 3 wells put the median at 85.7 mg/L. 23 surface samples from 4 sites put it at 13.5 mg/L. In Washington County the wells come out 4.2 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
Washington County against the rest of Maine
Among the 16 Maine counties with data, Washington County is number 14 of 16 counting from the hardest. Across the whole country it is harder than 8% of counties.
Softest in Maine: Lincoln County at 0.7 gpg. Hardest: Penobscot County at 6.9 gpg. Closest to Washington County: Sagadahoc County (0.8), Lincoln County (0.7), Piscataquis County (1.8).