Water Quality: Hollister, CA
21 water systems • 53,795 people served
Multiple Health ViolationsWater Quality Summary
Hollister has 38 health-based violations on record, meaning one or more contaminants were found above EPA-established safe levels. Contaminants involved: Barium, Contaminant 2920, Gross Alpha, Haloacetic Acids, Nitrate-Nitrite, Stage 2 DBP, TTHM. In total, 107 violations are on record for 21 water systems serving 53,795 people.
Contaminants Found
Water Systems Serving Hollister
| System Name | PWSID | Source | Population | Violations |
|---|---|---|---|---|
| HOLLISTER, CITY OF | CA3510001 | Surface Water | 26,017 | 25 |
| SUNNYSLOPE COUNTY WATER DIST | CA3510003 | Surface Water | 24,954 | 0 |
| RANCHO SAN JOAQUIN MWC | CA3500581 | Groundwater | 914 | 14 |
| CASA DE FRUTA WATER SYSTEM | CA4300611 | Groundwater | 250 | 3 |
| CSA NO. 31 STONEGATE WS | CA3500006 | Surface Water | 230 | 10 |
| SAN JUSTO MUTUAL WATER COMPANY | CA3500550 | Groundwater | 160 | 9 |
| HOLLISTER RANCH ESTATES | CA3500904 | Groundwater | 150 | 15 |
| ROSA MORADA MUTUAL WATER COMPANY | CA3500549 | Groundwater | 138 | 2 |
| ASHFORD HIGHLANDS MWC | CA3500900 | Groundwater | 132 | 0 |
| DUNNEVILLE ESTATES CSA #50 | CA3500910 | Groundwater | 120 | 0 |
| MCMAHON ROAD MUTUAL WATER COMPANY | CA3500510 | Groundwater | 102 | 1 |
| COMSTOCK MUTUAL WATER COMPANY | CA3500912 | Groundwater | 100 | 0 |
| UNION HEIGHTS MWC | CA3500825 | Groundwater | 98 | 1 |
| VINEYARD ESTATES MWC | CA3500579 | Groundwater | 90 | 6 |
| CREEKBRIDGE MUTUAL WATER COMPANY | CA3500911 | Groundwater | 69 | 0 |
| VALENZUELA WATER SYSTEM | CA3500527 | Groundwater | 55 | 14 |
| CASA DE FRUTA ORCHARDS | CA3500511 | Groundwater | 53 | 1 |
| VENTURE ESTATES MWC | CA3500552 | Groundwater | 50 | 1 |
| SPRINGWOOD ESTATES MWC | CA3500575 | Groundwater | 50 | 1 |
| WHISPERING PINES INN | CA3500810 | Groundwater | 38 | 4 |
| SAN BENITO COUNTY WATER DISTRICT | CA3510007 | Surface Water | 25 | 0 |
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.
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.