How hard is the water in Tehama County, CA?
6.6 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Tehama County, CA is 113 mg/L as calcium carbonate, which is 6.6 gpg. That is moderately hard on the USGS scale. It comes from 101 samples at 79 sites between 1996 and 2022, 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 4.8 and 9 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 6.6 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 Tehama 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 0.5 to 33.3 gpg
The softest single sample on record in Tehama County was 8.4 mg/L and the hardest 570 mg/L, a 68-fold gap. The top quarter of sites read above 9 gpg and the bottom quarter below 4.8 gpg.
Wells 6.6 gpg, rivers and lakes 2.6 gpg
101 groundwater samples from 79 wells put the median at 113 mg/L. 31 surface samples from 4 sites put it at 44.1 mg/L. In Tehama County the wells come out 4.0 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 24,000-grain unit covers a week between regenerations. Expect about 144 lb of salt a year (4 bags of 40 lb, about $26), 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 $126 a year.
Sizing at 6.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 396 | 24,000 | 48 lb |
| 2 | 792 | 24,000 | 96 lb |
| 4 | 1,584 | 24,000 | 193 lb |
| 6 | 2,376 | 24,000 | 289 lb |
Tehama County against the rest of California
Among the 58 California counties with data, Tehama County is number 37 of 58 counting from the hardest. Across the whole country it is harder than 37% of counties.
Softest in California: Sierra County at 1.7 gpg. Hardest: Calaveras County at 98.3 gpg. Closest to Tehama County: Butte County (6.5), Sacramento County (6.7), Amador County (6.3).