How hard is the water in Inyo County, CA?
3.9 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Inyo County, CA is 68 mg/L as calcium carbonate, which is 3.9 gpg. That is moderately hard on the USGS scale. It comes from 109 samples at 79 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 2.5 and 9.2 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 3.9 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one. Because Inyo 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 0.7 to 59.6 gpg
The softest single sample on record in Inyo County was 11.6 mg/L and the hardest 1,020 mg/L, an 88-fold gap. The top quarter of sites read above 9.2 gpg and the bottom quarter below 2.5 gpg.
Wells 3.9 gpg, rivers and lakes 4.5 gpg
109 groundwater samples from 79 wells put the median at 67.5 mg/L. 34 surface samples from 16 sites put it at 77 mg/L. In Inyo County the rivers and lakes come out 0.6 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.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 86 lb of salt a year (3 bags of 40 lb, about $16), 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 $116 a year.
Sizing at 3.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 234 | 24,000 | 28 lb |
| 2 | 468 | 24,000 | 57 lb |
| 4 | 936 | 24,000 | 114 lb |
| 6 | 1,404 | 24,000 | 171 lb |
Inyo County against the rest of California
Among the 58 California counties with data, Inyo County is number 52 of 58 counting from the hardest. Across the whole country it is harder than 26% of counties.
Softest in California: Sierra County at 1.7 gpg. Hardest: Calaveras County at 98.3 gpg. Closest to Inyo County: Modoc County (3.9), Plumas County (4.1), Marin County (3.6).