Water Hardness in California

58 counties — Average 146.2 PPM (Hard)

13
20
12
13
Soft (22.4%) Moderate (34.5%) Hard (20.7%) Very Hard (22.4%)

California Water Hardness Map

Soft   Moderate   Hard   Very Hard

Hardest Water Counties

Alameda240 PPM
Imperial370 PPM
Monterey226 PPM
Orange215.5 PPM
Riverside212 PPM
San Benito500 PPM
San Diego300 PPM
San Francisco251 PPM
San Luis Obispo617 PPM
Santa Barbara513.5 PPM
Santa Cruz245 PPM
Stanislaus236 PPM
+1 more
California

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All 58 Counties — By Water Hardness

CountyClassificationHardness
Alameda Very Hard 240 PPM
Alpine Soft 31 PPM
Amador Moderate 107 PPM
Butte Soft 50 PPM
Calaveras Moderate 97.5 PPM
Colusa Hard 180 PPM
Contra Costa Hard 170 PPM
Del Norte Moderate 61 PPM
El Dorado Soft 14 PPM
Fresno Moderate 120 PPM
Glenn Hard 140 PPM
Humboldt Moderate 74 PPM
Imperial Very Hard 370 PPM
Inyo Hard 170 PPM
Kern Hard 123 PPM
Kings Moderate 120 PPM
Lake Hard 130 PPM
Lassen Moderate 67 PPM
Los Angeles Hard 180 PPM
Madera Moderate 93 PPM
Marin Moderate 86 PPM
Mariposa Soft 7.2 PPM
Mendocino Moderate 78 PPM
Merced Hard 160 PPM
Modoc Soft 59 PPM
Mono Moderate 61.9 PPM
Monterey Very Hard 226 PPM
Napa Moderate 109 PPM
Nevada Soft 36 PPM
Orange Very Hard 215.5 PPM
Placer Soft 35 PPM
Plumas Moderate 65 PPM
Riverside Very Hard 212 PPM
Sacramento Soft 52.9 PPM
San Benito Very Hard 500 PPM
San Bernardino Hard 151 PPM
San Diego Very Hard 300 PPM
San Francisco Very Hard 251 PPM
San Joaquin Hard 130 PPM
San Luis Obispo Very Hard 617 PPM
San Mateo Moderate 65 PPM
Santa Barbara Very Hard 513.5 PPM
Santa Clara Hard 170 PPM
Santa Cruz Very Hard 245 PPM
Shasta Soft 44 PPM
Sierra Soft 33.8 PPM
Siskiyou Moderate 113 PPM
Solano Moderate 113 PPM
Sonoma Moderate 117 PPM
Stanislaus Very Hard 236 PPM
Sutter Moderate 74 PPM
Tehama Moderate 85 PPM
Trinity Soft 46 PPM
Tulare Soft 30 PPM
Tuolumne Soft 3.2 PPM
Ventura Very Hard 470 PPM
Yolo Hard 170 PPM
Yuba Moderate 63 PPM

Source: USGS Water Quality Portal

Frequently Asked Questions

How hard is the water in California?

California has an average water hardness of 146.2 PPM, classified as hard. Out of 58 counties, 13 have soft water, 20 moderately hard, 12 hard, and 13 very hard.

Which California counties have the hardest water?

California has 13 counties with very hard water (above 180 mg/L). See the county table above for a complete breakdown by hardness level.

How do I check water hardness for my California address?

Enter your ZIP code in the search box above to see your area's estimated water hardness, classification, and water utility information.