Water Quality: Three Rivers, CA
12 water systems • 10,513 people served
Multiple Health ViolationsWater Quality Summary
Three Rivers is served by 12 public water systems with a combined service population of 10,513 people, and has 208 EPA Safe Drinking Water Act violations on record. Critically, 128 of those are health-based violations, meaning one or more contaminants were detected above EPA-established safe levels — a serious public health concern. Three Rivers's violation count is 333% above the national average for California. Contaminants associated with violations include Barium, E. coli, Fecal Coliform, Gross Alpha, Stage 2 DBP.
Contaminants Found
Increases blood pressure and causes cardiovascular effects with long-term exposure.
Common source: Natural rock deposits, oil drilling operations, coal power plant waste
EPA limit: 2 mg/L
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)
Indicates direct fecal contamination; associated with diarrhea, cramps, nausea, and potential severe illness.
Common source: Human and animal fecal waste
EPA limit: Zero tolerance (any positive triggers violations)
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
Total trihalomethanes are linked to increased risk of bladder cancer and adverse reproductive outcomes.
Common source: Reaction of chlorine disinfectants with naturally occurring organic matter in water
EPA limit: 0.080 mg/L (80 ppb)
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 Three Rivers
| System Name | PWSID | Source | Population | Violations |
|---|---|---|---|---|
| NPS-GRANT GROVE | CA1010501 | Groundwater | 2,950 | 6 |
| NPS-WOLVERTON | CA5410503 | Surface Water | 2,940 | 117 |
| NPS-ASH MOUNTAIN | CA5410513 | Surface Water | 2,930 | 5 |
| NORTH KAWEAH MUTUAL WATER COMPANY | CA5400506 | Surface Water | 560 | 10 |
| SOUTH KAWEAH MUTUAL WATER COMPANY | CA5400754 | Groundwater | 384 | 16 |
| SIERRA KING HOMEOWNERS ASSN | CA5400940 | Groundwater | 260 | 0 |
| IMPROVEMENT DISTRICT NO. 1 | CA5400968 | Surface Water | 200 | 9 |
| SOUTH FORK ESTATES MUTUAL WATER CO | CA5403113 | Groundwater | 106 | 0 |
| DEER MEADOW MUTUAL WATER COMPANY | CA5401026 | Groundwater | 70 | 8 |
| RIVER RETREAT MUTUAL WATER COMPANY | CA5400556 | Groundwater | 40 | 22 |
| EAST THREE RIVERS MUTUAL WATER CORP | CA5400744 | Groundwater | 40 | 8 |
| VILLAGE APARTMENTS | CA5400875 | Groundwater | 33 | 7 |
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.