How hard is the water in Canyon County, ID?
10.7 grains per gallon
A softener will pay its way here.
The median hardness measured in Canyon County, ID is 183 mg/L as calcium carbonate, which is 10.7 gpg. That is very hard on the USGS scale. It comes from 859 samples at 231 sites between 1990 and 2019, 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 4.7 and 14.3 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
At 10.7 gpg a softener pays its way here. Before you buy, check the quoted unit's grain capacity against the sizing table below, and ask whether it regenerates on demand, which uses less salt than a timer. Call your utility for its own report if you are on city water. Because Canyon County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on sizing a softener for your household.
From 0.4 to 42.6 gpg
The softest single sample on record in Canyon County was 6.2 mg/L and the hardest 730 mg/L, a 118-fold gap. The top quarter of sites read above 14.3 gpg and the bottom quarter below 4.7 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 10.7 gpg, rivers and lakes 9.9 gpg
859 groundwater samples from 231 wells put the median at 183 mg/L. 117 surface samples from 22 sites put it at 170 mg/L. In Canyon 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.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 233 lb of salt a year (6 bags of 40 lb, about $42), and roughly 2,346 gallons of regeneration water. Installed, most units run $1,000 to $4,500; spread over 15 years with salt, that is about $142 a year.
Sizing at 10.7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 642 | 24,000 | 78 lb |
| 2 | 1,284 | 24,000 | 156 lb |
| 4 | 2,568 | 24,000 | 312 lb |
| 6 | 3,852 | 32,000 | 469 lb |
Canyon County against the rest of Idaho
Among the 44 Idaho counties with data, Canyon County is number 17 of 44 counting from the hardest. Across the whole country it is harder than 53% of counties.
Softest in Idaho: Valley County at 1.3 gpg. Hardest: Caribou County at 23 gpg. Closest to Canyon County: Teton County (10.9), Blaine County (10.3), Jefferson County (11.1).