How hard is the water in Salt Lake County, UT?
25.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Salt Lake County, UT is 443 mg/L as calcium carbonate, which is 25.9 gpg. That is very hard on the USGS scale. It comes from 899 samples at 320 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 16.4 and 41.9 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
At 25.9 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.
More on sizing a softener for your household.
From 1.2 to 221.8 gpg
The softest single sample on record in Salt Lake County was 20.9 mg/L and the hardest 3,796.2 mg/L, a 182-fold gap. The top quarter of sites read above 41.9 gpg and the bottom quarter below 16.4 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 25.9 gpg, rivers and lakes 19.8 gpg
899 groundwater samples from 320 wells put the median at 443.3 mg/L. 6,187 surface samples from 205 sites put it at 339.2 mg/L. In Salt Lake County the wells come out 6.1 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 40,000-grain unit covers a week between regenerations. Expect about 566 lb of salt a year (15 bags of 40 lb, about $102), 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 $202 a year.
Sizing at 25.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,554 | 24,000 | 189 lb |
| 2 | 3,108 | 24,000 | 378 lb |
| 4 | 6,216 | 48,000 | 756 lb |
| 6 | 9,324 | 80,000 | 1,134 lb |
Salt Lake County against the rest of Utah
Among the 29 Utah counties with data, Salt Lake County is number 4 of 29 counting from the hardest. Across the whole country it is harder than 92% of counties.
Softest in Utah: Davis County at 9 gpg. Hardest: Emery County at 151.3 gpg. Closest to Salt Lake County: Box Elder County (25.2), Uintah County (27.9), Juab County (28.5).