How hard is the water in Clark County, WA?

3 grains per gallon

You do not need a softener here.

The median hardness measured in Clark County, WA is 52 mg/L as calcium carbonate, which is 3 gpg. That is soft on the USGS scale. It comes from 164 samples at 8 sites between 1991 and 2024, drawn from every sampling site in the county, wells and surface water together.

How much it varies here

Half the sites came in between 1.1 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: medium (how it is measured).

What to do next

You can skip the softener. At 3 gpg the most a softener would fix is the odd water spot. If a salesperson in Clark County says otherwise, ask to see their reading in grains per gallon and compare it with this one. Because Clark 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 1.0 to 5.6 gpg

The softest single sample on record in Clark County was 17.9 mg/L and the hardest 96.4 mg/L, a 5-fold gap. The top quarter of sites read above 4.1 gpg and the bottom quarter below 1.1 gpg.

Clark County against the rest of Washington

Among the 38 Washington counties with data, Clark County is number 29 of 38 counting from the hardest. Across the whole country it is harder than 22% of counties.

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