How hard is the water in Ventura County, CA?
31.5 grains per gallon
A softener will pay its way here.
The median hardness measured in Ventura County, CA is 540 mg/L as calcium carbonate, which is 31.5 gpg. That is very hard on the USGS scale. It comes from 530 samples at 276 sites between 1990 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 22.1 and 42.9 gpg. The whole middle of that range gives the same answer, so a test of your own tap is unlikely to change it. Confidence in the county figure: high (how it is measured).
What to do next
At 31.5 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.
More on sizing a softener for your household.
From 4.0 to 282.7 gpg
The softest single sample on record in Ventura County was 67.9 mg/L and the hardest 4,840 mg/L, a 71-fold gap. The top quarter of sites read above 42.9 gpg and the bottom quarter below 22.1 gpg.
Wells 31.5 gpg, rivers and lakes 26.2 gpg
530 groundwater samples from 276 wells put the median at 540 mg/L. 20 surface samples from 12 sites put it at 448.5 mg/L. In Ventura County the wells come out 5.3 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 40,000-grain unit covers a week between regenerations. Expect about 689 lb of salt a year (18 bags of 40 lb, about $124), 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 $224 a year.
Sizing at 31.5 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,890 | 24,000 | 230 lb |
| 2 | 3,780 | 32,000 | 460 lb |
| 4 | 7,560 | 64,000 | 920 lb |
| 6 | 11,340 | 80,000 | 1,380 lb |
Ventura County against the rest of California
Among the 58 California counties with data, Ventura County is number 2 of 58 counting from the hardest. Across the whole country it is harder than 95% of counties.
Softest in California: Sierra County at 1.7 gpg. Hardest: Calaveras County at 98.3 gpg. Closest to Ventura County: San Luis Obispo County (30.7), Santa Barbara County (28.1), Contra Costa County (21.7).