How hard is the water in Riverside County, CA?
13.1 grains per gallon
A softener will pay its way here.
The median hardness measured in Riverside County, CA is 225 mg/L as calcium carbonate, which is 13.1 gpg. That is very hard on the USGS scale. It comes from 1,762 samples at 613 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 7.9 and 28 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 13.1 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 Riverside 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 251.5 gpg
The softest single sample on record in Riverside County was 2.7 mg/L and the hardest 4,305 mg/L, a 1,594-fold gap. The top quarter of sites read above 28 gpg and the bottom quarter below 7.9 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 13.1 gpg, rivers and lakes 9.1 gpg
1,762 groundwater samples from 613 wells put the median at 225 mg/L. 492 surface samples from 32 sites put it at 155.5 mg/L. In Riverside 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 287 lb of salt a year (8 bags of 40 lb, about $52), 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 $152 a year.
Sizing at 13.1 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 786 | 24,000 | 96 lb |
| 2 | 1,572 | 24,000 | 191 lb |
| 4 | 3,144 | 24,000 | 383 lb |
| 6 | 4,716 | 40,000 | 574 lb |
Riverside County against the rest of California
Among the 58 California counties with data, Riverside County is number 20 of 58 counting from the hardest. Across the whole country it is harder than 63% of counties.
Softest in California: Sierra County at 1.7 gpg. Hardest: Calaveras County at 98.3 gpg. Closest to Riverside County: San Francisco County (13.1), Glenn County (13.3), Santa Cruz County (12.9).