C52/100
HOLLISTER, CITY OF — Water Quality Report 2026
Serving 26,017 people · California
Water Source
Purchased Surface Water
County
—
System ID
CA3510001
Violations
18
Contaminant Test Results
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
chlorate | 860.00 µg/L | — | Above Goal |
Lead (90th percentile) | 0.002 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
3
Violations (last 5yr)
2
Unresolved
1
Health-Related
TIER 3Unresolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: April 1, 2024 – June 30, 2024Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 3Unresolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: April 1, 2024 – June 30, 2024Rule: Stage 2 DBPREnforcement: Formal — state order issuedVerify on EPA.gov
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: July 1, 2022 – September 30, 2022Rule: Stage 2 DBPREnforcement: Formal — state order issued
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Frequently Asked Questions About HOLLISTER, CITY OF
Is HOLLISTER, CITY OF water safe to drink?
HOLLISTER, CITY OF water receives a grade of C (52/100), which is considered fair. 0 contaminant(s) exceed EPA legal limits and 18 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has HOLLISTER, CITY OF detected?
69 contaminants were tested in HOLLISTER, CITY OF's water. Notable contaminants include Lead (90th percentile), chlorate. No contaminants exceed EPA legal limits. 2 exceed EPA health goals (MCLGs).
Does HOLLISTER, CITY OF have any EPA violations?
Yes, HOLLISTER, CITY OF has 18 EPA violation(s) on record, with the most recent in 2024. Violation types include MR, MCL, Other. 6 are health-based violations.
How many people does HOLLISTER, CITY OF serve?
HOLLISTER, CITY OF serves approximately 26,017 people, California. The system provides water to 1 community: Hollister.
What type of water does HOLLISTER, CITY OF provide?
HOLLISTER, CITY OF sources its water from purchased surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is CA3510001.
How does HOLLISTER, CITY OF compare to other utilities in California?
HOLLISTER, CITY OF scores 52/100 with a grade of C (fair). This score indicates room for improvement compared to other utilities. Visit our California state page for a full comparison of water systems.