How hard is the water in Kern County, CA?
10.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Kern County, CA is 187 mg/L as calcium carbonate, which is 10.9 gpg. That is very hard on the USGS scale. It comes from 523 samples at 274 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 5.2 and 24.6 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 10.9 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. Because Kern 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 0.2 to 240.7 gpg
The softest single sample on record in Kern County was 3.9 mg/L and the hardest 4,120 mg/L, a 1,056-fold gap. The top quarter of sites read above 24.6 gpg and the bottom quarter below 5.2 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 10.9 gpg, rivers and lakes 5.3 gpg
523 groundwater samples from 274 wells put the median at 187 mg/L. 29 surface samples from 5 sites put it at 90 mg/L. In Kern County the wells come out 5.6 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 239 lb of salt a year (6 bags of 40 lb, about $43), 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 $143 a year.
Sizing at 10.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 654 | 24,000 | 80 lb |
| 2 | 1,308 | 24,000 | 159 lb |
| 4 | 2,616 | 24,000 | 318 lb |
| 6 | 3,924 | 32,000 | 477 lb |
Kern County against the rest of California
Among the 58 California counties with data, Kern County is number 24 of 58 counting from the hardest. Across the whole country it is harder than 54% of counties.
Softest in California: Sierra County at 1.7 gpg. Hardest: Calaveras County at 98.3 gpg. Closest to Kern County: Lake County (9.8), Los Angeles County (12), Imperial County (9.5).