California Tap Water Quality by City
EPA UCMR5 PFAS monitoring, MCL / guideline flags, and WaterCheckup grades for 15 cities in California. "At Risk" means at least one UCMR analyte flagged above an EPA limit or a regulated PFAS violation on record for that system. "Monitor" means no such flag in UCMR data, but the city profile is medium or high concern. "Safe" means no exceedance flags and a low-concern city profile (still not a guarantee for every tap).
Average water hardness in California: 46.9 ppm → Mean of UCMR5 values for 6 tracked California cities (not every utility).
Five most common UCMR analytes with detections (>0) in our tracked California cities — each city counted once per compound.
| CITY | GRADE | CONTAMINANTS ABOVE LIMIT | POPULATION |
|---|---|---|---|
| Los Angeles Los Angeles Department of Water and Power | FMONITOR | — | 4M |
| San Diego San Diego Public Utilities | FMONITOR | — | 1.4M |
| San Jose San Jose Water Company | FAT RISK | 32 MCL violations | 1M |
| San Francisco SF Public Utilities Commission | FAT RISK | 44 MCL violations | 870K |
| Fresno City of Fresno Water Division | FAT RISK | 44 MCL violations | 540K |
| Sacramento Sacramento Regional Water Authority | FAT RISK | 32 MCL violations | 520K |
| Long Beach Long Beach Water Department | FAT RISK | 44 MCL violations | 460K |
| Bakersfield City of Bakersfield Water Resources | FAT RISK | 44 MCL violations | 380K |
| Anaheim City of Anaheim Public Utilities | FAT RISK | 33 MCL violations | 350K |
| Riverside Riverside Public Utilities | FMONITOR | — | 310K |
| Stockton City of Stockton Municipal Utilities | FAT RISK | 11 MCL violation | 310K |
| Chula Vista Sweetwater Authority | FMONITOR | — | 270K |
| Fremont Alameda County Water District | FAT RISK | 44 MCL violations | 230K |
| Modesto City of Modesto Utilities | FAT RISK | 44 MCL violations | 215K |
| Glendale Glendale Water and Power | FAT RISK | 44 MCL violations | 200K |
County-level grades roll up every WaterCheckup city we map into the same county (via USPS city–county reference data).
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California water quality varies by city and water system. UCMR5 reports PFAS and related analytes; the "above limit" column uses the EPA-limit flags bundled with each analyte in our dataset (same basis as city pages). Here, 11 of 15 tracked cities show at least one such flag or a regulated violation count.
SDWIS/City reports: use each city link for full narrative, picks, and EPA Consumer Confidence Report context.
Enter your ZIP code for the full EPA-linked report for your water system — PFAS, violations, and filter recommendations.
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