How hard is the water in Thurston County, WA?

3.3 grains per gallon

You do not need a softener here.

The median hardness measured in Thurston County, WA is 56 mg/L as calcium carbonate, which is 3.3 gpg. That is soft on the USGS scale. It comes from 51 samples at 19 sites between 1990 and 2016, 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 2.8 and 3.9 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 3.3 gpg the most a softener would fix is the odd water spot. If a salesperson in Thurston County says otherwise, ask to see their reading in grains per gallon and compare it with this one. Because Thurston 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 1.5 to 6.0 gpg

The softest single sample on record in Thurston County was 26.4 mg/L and the hardest 103.3 mg/L, a 4-fold gap. The top quarter of sites read above 3.9 gpg and the bottom quarter below 2.8 gpg.

Wells 3.3 gpg, rivers and lakes 2.4 gpg

51 groundwater samples from 19 wells put the median at 55.9 mg/L. 15 surface samples from 2 sites put it at 41.7 mg/L. In Thurston County the wells come out 0.9 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.

Thurston County against the rest of Washington

Among the 38 Washington counties with data, Thurston County is number 24 of 38 counting from the hardest. Across the whole country it is harder than 23% of counties.

Softest in Washington: Chelan County at 0.6 gpg. Hardest: Island County at 20.7 gpg. Closest to Thurston County: Benton County (3.3), Skamania County (3.3), Pierce County (3.2).