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Public water system

California Water Service-S San Francisco

PWSID CA4110009 - San Mateo County, California

386 PPM
22.5 GPG
Very Hard
0Soft60120180300+
Very Hard (386 PPM)Verified - State Lab Tested

System Details

Water source
surface water
Population served
64,146
Service connections
16,449
Status
Active

Hardness Evidence

Reported hardness
386 PPM
Grains per gallon
22.5 GPG
Data source
California treated-water report
Source year
2024
Raw/source estimate
192 PPM

Linked City Reports

Belmont, CABrisbane, CAHillsborough, CAColma, CADaly City, CAHalf Moon Bay, CALa Honda, CALoma Mar, CAWest Menlo Park, CAAtherton, CALadera, CAMillbrae, CAMontara, CAMoss Beach, CAPacifica, CAPescadero, CARedwood City, CAWoodside, CASan Bruno, CASan Carlos, CASan Gregorio, CASouth San Franci, CASan Francisco, CAEast Palo Alto, CARussian River, CASan Mateo, CAFoster City, CASan Jose, CA

Served ZIP Codes

ZIPLocationZIP average
94002Belmont, CAHard (241 PPM)
94005Brisbane, CAHard (241 PPM)
94010Hillsborough, CASlightly Hard (119 PPM)
94014Colma, CAHard (241 PPM)
94015Daly City, CAHard (241 PPM)
94019Half Moon Bay, CAHard (241 PPM)
94020La Honda, CAHard (241 PPM)
94021Loma Mar, CAHard (241 PPM)
94025West Menlo Park, CAHard (241 PPM)
94027Atherton, CAHard (241 PPM)
94028Ladera, CAHard (241 PPM)
94030Millbrae, CAHard (241 PPM)
94037Montara, CAHard (241 PPM)
94038Moss Beach, CAHard (241 PPM)
94044Pacifica, CAHard (241 PPM)
94060Pescadero, CAHard (241 PPM)
94061Redwood City, CAHard (241 PPM)
94062Woodside, CAHard (241 PPM)
94063Redwood City, CAHard (242 PPM)
94065Redwood City, CAHard (241 PPM)
94066San Bruno, CAHard (241 PPM)
94070San Carlos, CAHard (241 PPM)
94074San Gregorio, CAHard (241 PPM)
94080South San Franci, CAHard (241 PPM)
94128San Francisco, CAHard (241 PPM)
94303East Palo Alto, CAHard (242 PPM)
94401Russian River, CAHard (241 PPM)
94402San Mateo, CAHard (241 PPM)
94403San Mateo, CAHard (241 PPM)
94404Foster City, CAHard (241 PPM)
95112San Jose, CAHard (188 PPM)

How to Use This System Page

A public water system can serve multiple ZIP codes and cities. Use this page to inspect the source behind the hardness reading, then open the linked ZIP or city page for the local rollup.

If you are sizing treatment equipment, confirm your actual tap hardness with a home test or lab test before buying.

MethodologySourcesSearch by ZIP