Water Quality: Sonora, CA
14 water systems • 37,743 people served
Multiple Health ViolationsWater Quality Summary
Sonora is served by 14 public water systems with a combined service population of 37,743 people, and has 23 EPA Safe Drinking Water Act violations on record. Critically, 5 of those are health-based violations, meaning one or more contaminants were detected above EPA-established safe levels — a serious public health concern. Sonora's violation count is 52% below the national average for California. Contaminants associated with violations include E. coli, Gross Alpha, Stage 2 DBP, Total Haloacetic Acids (HAA5).
Contaminants Found
Causes gastrointestinal illness; certain strains (e.g., O157:H7) can cause severe kidney failure and death.
Common source: Fecal contamination from humans or animals entering the water supply
EPA limit: Zero (no E. coli permitted in drinking water)
Alpha-emitting radioactive particles increase cancer risk, particularly from bone and other internal cancers.
Common source: Natural uranium and radium in geological formations
EPA limit: 15 pCi/L (excluding radon and uranium)
Trihalomethanes and haloacetic acids that increase cancer risk and may cause adverse reproductive outcomes.
Common source: Chlorine disinfection reacting with natural organic matter in source water
EPA limit: TTHM: 0.080 mg/L; HAA5: 0.060 mg/L
Haloacetic acids are associated with increased cancer risk and potential reproductive and developmental effects.
Common source: Reaction of chlorine disinfectants with organic matter in treated water
EPA limit: 0.060 mg/L (60 ppb)
Water Systems Serving Sonora
| System Name | PWSID | Source | Population | Violations |
|---|---|---|---|---|
| TUD - UPPER BASIN WATER SYSTEM | CA5510012 | Surface Water | 13,280 | 0 |
| TUD - SONORA/JAMESTOWN WATER SYSTEM | CA5510001 | Surface Water | 11,054 | 1 |
| TUD - COLUMBIA WATER SYSTEM | CA5510013 | Surface Water | 5,463 | 0 |
| TUD - PONDEROSA | CA5510002 | Surface Water | 1,767 | 2 |
| TUD - TUOLUMNE WATER SYSTEM | CA5510003 | Surface Water | 1,761 | 1 |
| PHOENIX LAKE ESTATES CC MWC | CA5510026 | Groundwater | 1,168 | 2 |
| SONORA MEADOWS MUTUAL WTR CO | CA5510023 | Surface Water | 1,123 | 6 |
| TUD-APPLE VALLEY ESTATES | CA5510028 | Groundwater | 826 | 1 |
| BELLEVIEW OAKS MUTUAL WATER CO | CA5500042 | Groundwater | 468 | 1 |
| SLIDE INN SNOWBOWL WATER CO | CA5500077 | Groundwater | 417 | 1 |
| MOTHER LODE MOBILE ESTATES | CA5500125 | Groundwater | 210 | 1 |
| TUD-PEACEFUL PINES WATER SYSTEM | CA5510021 | Groundwater | 92 | 0 |
| TUD-WARDS FERRY RANCHES | CA5500363 | Groundwater | 62 | 2 |
| PONDEROSA MOBILE HOME PARK | CA5500092 | Groundwater | 52 | 5 |
Concerned About Your Water?
A home water filter can remove common contaminants. NSF-certified filters are tested against EPA standards.
Consider a reverse osmosis system for comprehensive filtration or a carbon filter for basic improvement.
Other Cities in California
Data Sources
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). Data includes all recorded violations for active community water systems.