How hard is the water in Boise County, ID?

2 grains per gallon

You do not need a softener here.

The median hardness measured in Boise County, ID is 34 mg/L as calcium carbonate, which is 2 gpg. That is soft on the USGS scale. It comes from 109 samples at 22 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 1.3 and 2.8 gpg. The whole middle of that range gives the same answer, so a test of your own tap is unlikely to change it. Confidence in the county figure: high (how it is measured).

What to do next

You can skip the softener. At 2 gpg the most a softener would fix is the odd water spot. If a salesperson in Boise County says otherwise, ask to see their reading in grains per gallon and compare it with this one.

More on when a softener is not worth it.

From 0.6 to 6.4 gpg

The softest single sample on record in Boise County was 11 mg/L and the hardest 109.5 mg/L, a 10-fold gap. The top quarter of sites read above 2.8 gpg and the bottom quarter below 1.3 gpg.

Wells 2 gpg, rivers and lakes 2 gpg

109 groundwater samples from 22 wells put the median at 33.6 mg/L. 29 surface samples from 2 sites put it at 33.9 mg/L. In Boise County the rivers and lakes come out 0.0 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. The two sources are close, so the county figure should hold whichever one your tap is on.

Boise County against the rest of Idaho

Among the 44 Idaho counties with data, Boise County is number 43 of 44 counting from the hardest. Across the whole country it is harder than 16% of counties.

Softest in Idaho: Valley County at 1.3 gpg. Hardest: Caribou County at 23 gpg. Closest to Boise County: Valley County (1.3), Camas County (3.2), Adams County (3.2).