How hard is the water in New London County, CT?

2.3 grains per gallon

You do not need a softener here.

The median hardness measured in New London County, CT is 39 mg/L as calcium carbonate, which is 2.3 gpg. That is soft on the USGS scale. It comes from 40 samples at 31 sites between 1990 and 2023, drawn from groundwater wells, which is what most taps and private wells in the county draw on.

How much it varies here

Half the sites came in between 1.5 and 4.1 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: high (how it is measured).

What to do next

You can skip the softener. At 2.3 gpg the most a softener would fix is the odd water spot. If a salesperson in New London County says otherwise, ask to see their reading in grains per gallon and compare it with this one. Because New London 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 0.5 to 70.1 gpg

The softest single sample on record in New London County was 8.7 mg/L and the hardest 1,200 mg/L, a 138-fold gap. The top quarter of sites read above 4.1 gpg and the bottom quarter below 1.5 gpg. So even in a soft county, a handful of wells here produce water hard enough to scale a heater.

Wells 2.3 gpg, rivers and lakes 1.5 gpg

40 groundwater samples from 31 wells put the median at 39 mg/L. 395 surface samples from 15 sites put it at 26.2 mg/L. In New London County the wells come out 0.8 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. The two sources are close, so the county figure should hold whichever one your tap is on.

New London County against the rest of Connecticut

Among the 8 Connecticut counties with data, New London County is the softest. Across the whole country it is harder than 18% of counties.

Hardest: New Haven County at 6.1 gpg. Closest to New London County: Fairfield County (3), Middlesex County (3), Windham County (3.9).