PlainWater

Community Water System · PWS CA3510001

Hollister, City Of

Hollister, California 95023 - drinking water served from surface water sources to 26,017 people, tracked in EPA SDWIS and UCMR5.

26,017
People served
35
EPA violations
12
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 35 drinking-water violations at Hollister, City Of, 34% of them health-based - above the California per-system average.

35
Total EPA violations on record
34%
Health-based (MCL / treatment failure)
26,017
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Hollister, City Of

Hollister, City Of is a local-owned community water system that delivers drinking water to 26,017 residents in Hollister, California (San Benito County) through 7,884 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 35 total violations for this system , of which 12 (34%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 20 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is TTHM, recorded in 10 violations (MCL, health-based). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

Across California, EPA tracks 7,249 public water systems serving 42,404,883 people, with 153,308 cumulative violations and 63,983 health-based violations on record. About 89% of systems in the state carry at least one violation, and state-wide the average per system is 21.1 violations. Statewide, 447 of 694 UCMR5-tested systems have reported PFAS detections (64.4%).

Hollister, City Of's 35 violations sit above the California average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

Population Served
26,017
Total Violations
35
Health-Based Violations
12
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
7,884
County
San Benito
School/Daycare
No
MCL Violations
12
Monitoring Violations
20
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
TTHM MCL 10 2022
Nitrate MR 8 2010
Coliform (TCR) MR 4 2015
Benzene MR 4 1999
Combined Uranium MR 2 2002
Nitrate MCL 2 1999
TTHM MR 1 2024
Total Haloacetic Acids (HAA5) MR 1 2024

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 638 samples detected PFAS.

Contaminant Date Result MRL Status
PFMPA 8/15/2024 <4.00 ppt 4.00 ppt Not Detected
PFDoA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFUnA 8/15/2024 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
9Cl-PF3ONS 8/15/2024 <2.00 ppt 2.00 ppt Not Detected
ADONA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
PFBA 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
PFDA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
NFDHA 8/15/2024 <20.00 ppt 20.00 ppt Not Detected
PFPeA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFMBA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFEESA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeS 8/15/2024 <4.00 ppt 4.00 ppt Not Detected
PFTA 8/15/2024 <8.00 ppt 8.00 ppt Not Detected
PFTrDA 8/15/2024 <7.00 ppt 7.00 ppt Not Detected
NEtFOSAA 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 8/15/2024 <6.00 ppt 6.00 ppt Not Detected
4:2 FTS 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFOS 8/15/2024 <4.00 ppt 4.00 ppt Not Detected
PFNA 8/15/2024 <4.00 ppt 4.00 ppt Not Detected
PFHxS 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFHpA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFBS 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFOA 8/15/2024 <4.00 ppt 4.00 ppt Not Detected
PFHpS 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
NFDHA 8/15/2024 <20.00 ppt 20.00 ppt Not Detected
PFTA 8/15/2024 <8.00 ppt 8.00 ppt Not Detected
PFHpA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFBS 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFMPA 8/15/2024 <4.00 ppt 4.00 ppt Not Detected
PFPeA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFEESA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeS 8/15/2024 <4.00 ppt 4.00 ppt Not Detected
PFHpS 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
NEtFOSAA 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 8/15/2024 <6.00 ppt 6.00 ppt Not Detected
PFMBA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFUnA 8/15/2024 <2.00 ppt 2.00 ppt Not Detected
4:2 FTS 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
6:2 FTS 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
8:2 FTS 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
PFBA 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 8/15/2024 <5.00 ppt 5.00 ppt Not Detected
ADONA 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxS 8/15/2024 <3.00 ppt 3.00 ppt Not Detected
11Cl-PF3OUdS 8/15/2024 <5.00 ppt 5.00 ppt Not Detected

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Hollister, City Of.

Federal Source of Truth

EPA SDWIS, Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID CA3510001 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

California Drinking Water Authority

California State Water Resources Control Board, Division of Drinking Water is the primacy agency that licenses and inspects Hollister, City Of under EPA-delegated authority.

Open CA regulator portal

Source: California State Water Resources Control Board, Division of Drinking Water

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2024 TTHM MR 1 SDWIS / CA3510001 / 2950
2024 Total Haloacetic Acids (HAA5) MR 1 SDWIS / CA3510001 / 2456
2022 TTHM MCL 10 SDWIS / CA3510001 / 2950
2015 Coliform (TCR) MR 4 SDWIS / CA3510001 / 3100
2010 Nitrate MR 8 SDWIS / CA3510001 / 1040
2002 Combined Uranium MR 2 SDWIS / CA3510001 / 4006
1999 Benzene MR 4 SDWIS / CA3510001 / 2990
1999 Nitrate MCL 2 SDWIS / CA3510001 / 1040

How Hollister, City Of Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric Hollister, City Of California avg Federal benchmark
Total violations 35 21.1 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 12 8.8 Indicates a contaminant exceeded a federal MCL
PFAS detection None 64.4% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 26,017 5,850 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 7,249 regulated public water systems in California.

Federal MCL reference, Safe Drinking Water Act thresholds
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Hollister, City Of water safe to drink?
Hollister, City Of (PWS ID: CA3510001) has 35 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 26,017 people using Surface Water sources.
How many people does Hollister, City Of serve?
Hollister, City Of serves 26,017 people in Hollister, California. It is a Local-owned system using Surface Water water sources with 7,884 service connections.
What type of violations does Hollister, City Of have?
Hollister, City Of has 35 total violations: 12 health-based violations (MCL exceedances or treatment failures), 20 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Hollister, City Of water?
No. Hollister, City Of was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does Hollister, City Of use?
Hollister, City Of uses Surface Water as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from?
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. PFAS data from EPA UCMR5 monitoring program (2023-2025). This data is provided for informational purposes only.
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.