How hard is the water in Modoc County, CA?
3.9 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Modoc County, CA is 66 mg/L as calcium carbonate, which is 3.9 gpg. That is moderately hard on the USGS scale. It comes from 27 samples at 16 sites between 2000 and 2020, 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 3.4 and 8.3 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: medium (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 Modoc 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 0.1 to 26.8 gpg
The softest single sample on record in Modoc County was 2.2 mg/L and the hardest 459 mg/L, a 209-fold gap. The top quarter of sites read above 8.3 gpg and the bottom quarter below 3.4 gpg.
Wells 3.9 gpg, rivers and lakes 1.5 gpg
27 groundwater samples from 16 wells put the median at 66.3 mg/L. 6 surface samples from 2 sites put it at 25.7 mg/L. In Modoc County the wells come out 2.4 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 85 lb of salt a year (3 bags of 40 lb, about $15), 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 $115 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 |
Modoc County against the rest of California
Among the 58 California counties with data, Modoc County is number 53 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 Modoc County: Inyo County (3.9), Marin County (3.6), Plumas County (4.1).