California
Water quality data from the EPA Safe Drinking Water Information System
Water Systems
20,579
Active public water systems
Population Served
42.72M
Residents with piped water
Lead Violations
142
Systems exceeding 15 ppb
Copper Violations
569
Lead & Copper Rule
Average Lead Level
EPA Action Level: 15 ppb
MCLG (health goal): 0 ppb
Average across 5423 systems with reported lead data.
Violations Detected
711 water systems in California have reported violations under the Lead and Copper Rule. These utilities are required to notify customers and take corrective action.
Schools & Daycares
9 school or daycare water systems identified in this state. 1 have active violations.
Children are especially vulnerable to lead exposure. Schools are required to test for lead and remediate violations.
Water Systems: Highest Lead Levels
| System Name | City | Population | Lead Level | Status | Sample Date |
|---|---|---|---|---|---|
| BAKERSFIELD | 19,400 | 22.00 ppb | Violation | 1996-06-30 | |
| PLEASANTON | 76,689 | 21.80 ppb | Violation | 2022-12-31 | |
| 29 PALMS | 15,248 | 20.00 ppb | Violation | 2024-12-31 | |
| MOFFETT FIELD | 16,273 | 10.42 ppb | OK | 2023-12-31 | |
SAN JOSE STATE UNIVERSITYSchool/Daycare | SAN JOSE | 34,861 | 10.30 ppb | OK | 2021-12-31 |
| CORCORAN | 22,808 | 9.30 ppb | OK | 2024-12-31 | |
| LA VERNE | 31,334 | 9.00 ppb | OK | 2024-12-31 | |
| SONORA | 11,054 | 8.10 ppb | OK | 2025-12-31 | |
| BEAUMONT | 66,841 | 7.80 ppb | OK | 2024-12-31 | |
| SAN JOSE | 60,414 | 7.50 ppb | OK | 2024-12-31 | |
| HILLSBOROUGH | 11,766 | 6.50 ppb | OK | 2022-12-31 | |
| LIVERMORE | 10,870 | 6.40 ppb | OK | 2023-12-31 | |
| FOUNTAIN VALLEY | 56,747 | 6.00 ppb | OK | 2024-12-31 | |
| RAMONA | 25,068 | 6.00 ppb | OK | 2025-06-30 | |
| SACRAMENTO | 15,652 | 6.00 ppb | OK | 2024-12-31 |
Showing top 15 of 5191 systems with lead data. Action level: 15 ppb.
Systems With Active Violations
These water systems have exceeded EPA limits and must take corrective action.
FREMONT · Pop. 344,000
Lead: 0.00 ppb (2024-12-31)
SANTA ROSA · Pop. 175,396
Lead: 0.00 ppb (2022-12-31)
CORONA · Pop. 168,575
Lead: 3.00 ppb (2023-12-31)
ANTIOCH · Pop. 115,074
Lead: 0.00 ppb (2024-12-31)
SOUTH LAKE TAHOE · Pop. 100,000
Lead: 0.00 ppb (2023-12-31)
PLEASANTON · Pop. 98,776
Lead: 0.00 ppb (2025-12-31)
SANTA CRUZ · Pop. 94,626
Lead: 0.00 ppb (2024-12-31)
PACIFIC GROVE · Pop. 92,450
Lead: 2.00 ppb (2024-12-31)
PLEASANTON · Pop. 76,689
Lead: 21.80 ppb (2022-12-31)
BIG BEAR LAKE · Pop. 75,500
Lead: 0.00 ppb (2024-12-31)
WATSONVILLE · Pop. 65,231
Lead: 2.10 ppb (2022-12-31)
NOVATO · Pop. 61,691
Lead: 0.00 ppb (2023-12-31)
Water Source Types
Air Quality
ModerateAvg AQI
55.5
PM2.5
7.8 µg/m³
Unhealthy Days
18
Primary Pollutant
Ozone, PM2.5
Source: EPA AirNow & American Lung Association 2024 State of the Air. AQI scale: 0–50 Good · 51–100 Moderate · 101–150 Sensitive Groups · 151+ Unhealthy.
PFAS Contamination
Moderate DetectionPFAS (per- and polyfluoroalkyl substances), known as “forever chemicals,” are a group of synthetic chemicals that persist indefinitely in the environment and human body. The EPA set a maximum contaminant level (MCL) of 4 parts per trillion (ppt) for PFOA and PFOS in April 2024. View national PFAS tracker →
Systems Tested
760
PFAS Detected
263
Detection Rate
34.6%
Exceeding MCL (4 ppt)
56(7.4%)
Highest recorded level: 110 ppt (EPA MCL: 4 ppt). EWG: 263 systems with PFAS above proposed limits. State water board began monitoring in 2019. Large systems in LA, SF Bay Area affected. 69% of disadvantaged communities have PFAS (NRDC)