How hard is the water in Los Angeles County, CA?
12 grains per gallon
A softener will pay its way here.
The median hardness measured in Los Angeles County, CA is 206 mg/L as calcium carbonate, which is 12 gpg. That is very hard on the USGS scale. It comes from 1,660 samples at 726 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 6.8 and 18.1 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 12 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 Los Angeles 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 0.4 to 233.1 gpg
The softest single sample on record in Los Angeles County was 6.6 mg/L and the hardest 3,990 mg/L, a 605-fold gap. The top quarter of sites read above 18.1 gpg and the bottom quarter below 6.8 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 12 gpg, rivers and lakes 12.4 gpg
1,660 groundwater samples from 726 wells put the median at 205.8 mg/L. 145 surface samples from 50 sites put it at 212 mg/L. In Los Angeles County the rivers and lakes come out 0.4 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 263 lb of salt a year (7 bags of 40 lb, about $47), 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 $147 a year.
Sizing at 12 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 720 | 24,000 | 88 lb |
| 2 | 1,440 | 24,000 | 175 lb |
| 4 | 2,880 | 24,000 | 350 lb |
| 6 | 4,320 | 32,000 | 526 lb |
Los Angeles County against the rest of California
Among the 58 California counties with data, Los Angeles County is number 23 of 58 counting from the hardest. Across the whole country it is harder than 59% of counties.
Softest in California: Sierra County at 1.7 gpg. Hardest: Calaveras County at 98.3 gpg. Closest to Los Angeles County: Santa Cruz County (12.9), San Francisco County (13.1), Kern County (10.9).