Hollister Water Quality
California
According to EPA SDWIS, Hollister, California is served by 21 community water systems covering about 53,795 people. The same extract lists 38 health-based violation records, most recently coded 5200 in 2024. Counts are historical EPA registry rows, not a current compliance or drinkability score.
Drinking water in Hollister, California is delivered through 21 EPA-regulated community water systems serving an estimated 53,795 people. Each system is tracked in the EPA Safe Drinking Water Information System (SDWIS) under the Safe Drinking Water Act, which requires testing for regulated contaminants, consumer notification of violations, and publication of an annual Consumer Confidence Report.
PlainEnviro's health-based SDWIS extract shows 38 violation records across the 21 active community systems shown here. Monitoring and reporting records are not present in the extract. The records carry 7 distinct EPA contaminant codes: LEAD AND COPPER RULE REVISIONS, Arsenic, TTHM, CARBON, TOTAL, Nitrate-Nitrite and 2 others. 5 TRI-reporting industrial facilities are also located within the city limits.
A past EPA health-based registry row does not describe water delivered today or current compliance status; utilities notify customers and remediate under state primacy oversight when required. For current water-quality status and treatment practices, review your local utility's most recent Consumer Confidence Report or contact the California drinking water program. All records above reflect federal EPA SDWIS data and are not independently verified against state databases.
Community Water Systems
| System Name | Pop. Served | Violations | Status |
|---|---|---|---|
| HOLLISTER, CITY OF | 26,017 | 17 | Health |
| SUNNYSLOPE COUNTY WATER DIST | 24,954 | 0 | Clean |
| RANCHO SAN JOAQUIN MWC | 914 | 5 | Health |
| CASA DE FRUTA WATER SYSTEM | 250 | 2 | Health |
| CSA NO. 31 STONEGATE WS | 230 | 3 | Health |
| SAN JUSTO MUTUAL WATER COMPANY | 160 | 1 | Health |
| HOLLISTER RANCH ESTATES | 150 | 8 | Health |
| ROSA MORADA MUTUAL WATER COMPANY | 138 | 0 | Clean |
| ASHFORD HIGHLANDS MWC | 132 | 0 | Clean |
| DUNNEVILLE ESTATES CSA #50 | 120 | 0 | Clean |
| MCMAHON ROAD MUTUAL WATER COMPANY | 102 | 0 | Clean |
| COMSTOCK MUTUAL WATER COMPANY | 100 | 0 | Clean |
| UNION HEIGHTS MWC | 98 | 0 | Clean |
| VINEYARD ESTATES MWC | 90 | 0 | Clean |
| CREEKBRIDGE MUTUAL WATER COMPANY | 69 | 0 | Clean |
| VALENZUELA WATER SYSTEM | 55 | 2 | Health |
| CASA DE FRUTA ORCHARDS | 53 | 0 | Clean |
| VENTURE ESTATES MWC | 50 | 0 | Clean |
| SPRINGWOOD ESTATES MWC | 50 | 0 | Clean |
| WHISPERING PINES INN | 38 | 0 | Clean |
| SAN BENITO COUNTY WATER DISTRICT | 25 | 0 | Clean |
Does this city have health-based water violations?
These health-based records can represent Maximum Contaminant Level (MCL), Treatment Technique (TT), or Maximum Residual Disinfectant Level (MRDL) categories. A historical record does not establish that water is currently unsafe.
| Water system | Contaminant | Begin Date |
|---|---|---|
| CASA DE FRUTA WATER SYSTEM | LEAD AND COPPER RULE REVISIONS | 2024-10-17 |
| RANCHO SAN JOAQUIN MWC | LEAD AND COPPER RULE REVISIONS | 2024-10-17 |
| SAN JUSTO MUTUAL WATER COMPANY | LEAD AND COPPER RULE REVISIONS | 2024-10-17 |
| RANCHO SAN JOAQUIN MWC | Arsenic | 2023-07-01 |
| RANCHO SAN JOAQUIN MWC | Arsenic | 2023-07-01 |
| RANCHO SAN JOAQUIN MWC | Arsenic | 2022-10-01 |
| RANCHO SAN JOAQUIN MWC | Arsenic | 2022-10-01 |
| HOLLISTER, CITY OF | TTHM | 2022-07-01 |
| HOLLISTER, CITY OF | TTHM | 2022-07-01 |
| HOLLISTER, CITY OF | TTHM | 2022-07-01 |
| HOLLISTER, CITY OF | TTHM | 2022-07-01 |
| HOLLISTER, CITY OF | TTHM | 2022-07-01 |
| CSA NO. 31 STONEGATE WS | CARBON, TOTAL | 2022-04-01 |
| CSA NO. 31 STONEGATE WS | CARBON, TOTAL | 2022-04-01 |
| CSA NO. 31 STONEGATE WS | CARBON, TOTAL | 2022-04-01 |
| HOLLISTER, CITY OF | TTHM | 2018-10-01 |
| HOLLISTER, CITY OF | TTHM | 2018-10-01 |
| HOLLISTER, CITY OF | TTHM | 2018-10-01 |
| HOLLISTER, CITY OF | TTHM | 2018-07-01 |
| HOLLISTER, CITY OF | TTHM | 2018-07-01 |
| HOLLISTER, CITY OF | TTHM | 2018-07-01 |
| VALENZUELA WATER SYSTEM | Nitrate-Nitrite | 2018-05-01 |
| VALENZUELA WATER SYSTEM | Nitrate-Nitrite | 2018-04-01 |
| HOLLISTER RANCH ESTATES | Combined Uranium | 2017-07-01 |
| HOLLISTER RANCH ESTATES | Combined Uranium | 2017-04-01 |
| HOLLISTER RANCH ESTATES | Combined Uranium | 2017-01-01 |
| HOLLISTER RANCH ESTATES | Combined Uranium | 2016-10-01 |
| HOLLISTER RANCH ESTATES | Combined Uranium | 2016-07-01 |
| HOLLISTER RANCH ESTATES | Combined Uranium | 2016-04-01 |
| HOLLISTER, CITY OF | TTHM | 2016-01-01 |
| HOLLISTER, CITY OF | TTHM | 2016-01-01 |
| HOLLISTER, CITY OF | TTHM | 2016-01-01 |
| HOLLISTER RANCH ESTATES | Combined Uranium | 2016-01-01 |
| HOLLISTER, CITY OF | TTHM | 2015-10-01 |
| HOLLISTER, CITY OF | TTHM | 2015-10-01 |
| HOLLISTER, CITY OF | TTHM | 2015-10-01 |
| HOLLISTER RANCH ESTATES | Combined Uranium | 2015-10-01 |
| CASA DE FRUTA WATER SYSTEM | Coliform (TCR) | 1994-07-01 |
What are Hollister's health-based records for?
Hollister's health-based violation records carry 7 distinct EPA codes: some name a substance, others the drinking-water rule that was breached. Counts are records on file in the EPA SDWIS extract, not current test results.
| Contaminant | Records | Systems |
|---|---|---|
| Tthm | 17 | 1 |
| Combined Uranium | 8 | 1 |
| Arsenic | 4 | 1 |
| Lead and Copper Rule Revisions | 3 | 3 |
| Carbon, Total | 3 | 1 |
| Nitrate-Nitrite | 2 | 1 |
| Coliform (TCR) | 1 | 1 |
TRI Facilities in Hollister
| Facility | Total Releases |
|---|---|
| Fujifilm Electronic Materials USA Inc. | 40.8K lbs |
| Trical Inc | 15.2K lbs |
| Royal Circuit Solutions Inc. | 6.3K lbs |
| Pacific Scientific Energetics Materials Co California | 4.8K lbs |
| Pride Conveyance Systems | 397 lbs |
Frequently Asked Questions
What does EPA SDWIS list for drinking water in Hollister, California? ▼
How many water violations does Hollister have in this EPA extract? ▼
What contaminants were found in Hollister water? ▼
How many water systems serve Hollister? ▼
Where does Hollister get its drinking water? ▼
Are there pollution sources near Hollister? ▼
How does Hollister compare in California?
Of the 909 California places with at least one community water system on file, Hollister ranks #12 by number of systems (21).
Either side of it: Bishop (24), Los Angeles (22), Red Bluff (20), San Luis Obispo (20)
About This Data
Figures here are the current EPA SDWIS extract joined to the 21 community water systems whose service area lists Hollister, ranked against the 909 California places with at least one system on file. Data current as of 2026-08-25.
Water system data comes from the EPA's Safe Drinking Water Information System (SDWIS). PlainEnviro's violation fetch is restricted upstream to records EPA flags as health-based and then joined to active community water systems. Monitoring and reporting violations are not included.
A health-based violation row in this extract is a historical EPA registry entry. It does not describe water delivered today or current compliance status. Many records are later resolved, and public water systems notify customers when required. For current conditions, contact your local water utility or the state drinking water program.
TRI facility data comes from the EPA Toxic Release Inventory. Facilities shown are those that self-report to the TRI program. PlainEnviro presents this data without advocacy framing.
Read our methodology - how this data is sourced, computed, and verified.