How hard is the water in Sullivan County, NY?

3.2 grains per gallon

You do not need a softener here.

The median hardness measured in Sullivan County, NY is 54 mg/L as calcium carbonate, which is 3.2 gpg. That is soft on the USGS scale. It comes from 24 samples at 17 sites between 1991 and 2025, 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 2.4 and 5.1 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: medium (how it is measured).

What to do next

You can skip the softener. At 3.2 gpg the most a softener would fix is the odd water spot. If a salesperson in Sullivan County says otherwise, ask to see their reading in grains per gallon and compare it with this one. Because Sullivan 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 0.8 to 10.1 gpg

The softest single sample on record in Sullivan County was 13.9 mg/L and the hardest 172.5 mg/L, a 12-fold gap. The top quarter of sites read above 5.1 gpg and the bottom quarter below 2.4 gpg.

Wells 3.2 gpg, rivers and lakes 1.1 gpg

24 groundwater samples from 17 wells put the median at 54.4 mg/L. 1,853 surface samples from 63 sites put it at 19.2 mg/L. In Sullivan County the wells come out 2.1 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.

Sullivan County against the rest of New York

Among the 61 New York counties with data, Sullivan County is number 58 of 61 counting from the hardest. Across the whole country it is harder than 22% of counties.

Softest in New York: Suffolk County at 1.6 gpg. Hardest: New York County at 161.1 gpg. Closest to Sullivan County: Delaware County (3.4), Franklin County (3.4), Nassau County (2.8).