How hard is the water in Lewis County, ID?
7.9 grains per gallon
A softener is worth it here.
The median hardness measured in Lewis County, ID is 135 mg/L as calcium carbonate, which is 7.9 gpg. That is hard on the USGS scale. It comes from 63 samples at 20 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 6.8 and 9.5 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 7.9 gpg a softener is worth getting, mainly to protect the water heater and cut soap use. Get at least two quotes, ask each installer what grain capacity they are fitting, and check it against the sizing table below. Because Lewis 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 4.0 to 24.4 gpg
The softest single sample on record in Lewis County was 69.1 mg/L and the hardest 418 mg/L, a 6-fold gap. The top quarter of sites read above 9.5 gpg and the bottom quarter below 6.8 gpg.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 172 lb of salt a year (5 bags of 40 lb, about $31), 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 $131 a year.
Sizing at 7.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 474 | 24,000 | 58 lb |
| 2 | 948 | 24,000 | 115 lb |
| 4 | 1,896 | 24,000 | 231 lb |
| 6 | 2,844 | 24,000 | 346 lb |
Lewis County against the rest of Idaho
Among the 44 Idaho counties with data, Lewis County is number 26 of 44 counting from the hardest. Across the whole country it is harder than 42% of counties.
Softest in Idaho: Valley County at 1.3 gpg. Hardest: Caribou County at 23 gpg. Closest to Lewis County: Washington County (7.6), Lincoln County (8.2), Ada County (7.4).