How hard is the water in Yolo County, CA?
14.1 grains per gallon
A softener will pay its way here.
The median hardness measured in Yolo County, CA is 242 mg/L as calcium carbonate, which is 14.1 gpg. That is very hard on the USGS scale. It comes from 30 samples at 17 sites between 1996 and 2021, 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 8.8 and 18.6 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 14.1 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 Yolo 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 2.9 to 30.8 gpg
The softest single sample on record in Yolo County was 48.9 mg/L and the hardest 527 mg/L, an 11-fold gap. The top quarter of sites read above 18.6 gpg and the bottom quarter below 8.8 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 14.1 gpg, rivers and lakes 5.7 gpg
30 groundwater samples from 17 wells put the median at 242 mg/L. 67 surface samples from 4 sites put it at 97.1 mg/L. In Yolo County the wells come out 8.4 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. 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 309 lb of salt a year (8 bags of 40 lb, about $56), 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 $156 a year.
Sizing at 14.1 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 846 | 24,000 | 103 lb |
| 2 | 1,692 | 24,000 | 206 lb |
| 4 | 3,384 | 24,000 | 412 lb |
| 6 | 5,076 | 40,000 | 618 lb |
Yolo County against the rest of California
Among the 58 California counties with data, Yolo County is number 15 of 58 counting from the hardest. Across the whole country it is harder than 67% of counties.
Softest in California: Sierra County at 1.7 gpg. Hardest: Calaveras County at 98.3 gpg. Closest to Yolo County: Sutter County (14.2), Fresno County (14), Alameda County (14).