PlainWater

SAN JUSTO MUTUAL WATER COMPANY

PWS ID: CA3500550 · HOLLISTER, California 95023

SAN JUSTO MUTUAL WATER COMPANY serves 160 people in HOLLISTER, California using Groundwater water sources. It has 74 recorded EPA violations, including 26 health-based violations. No PFAS contamination was detected in UCMR5 testing.

Water Quality Snapshot: SAN JUSTO MUTUAL WATER COMPANY

SAN JUSTO MUTUAL WATER COMPANY is a private-owned community water system that delivers drinking water to 160 residents in HOLLISTER, California (San Benito County) through 61 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 74 total violations for this system , of which 26 (35%) are health-based — meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 41 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 Coliform (TCR), recorded in 28 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

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. SAN JUSTO MUTUAL WATER COMPANY's 74 violations sit above the California average. Statewide, 447 of 694 UCMR5-tested systems have reported PFAS detections (64.4%). 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
160
Total Violations
74
Health-Based Violations
26
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Private
Connections
61
County
San Benito
School/Daycare
No
MCL Violations
25
Monitoring Violations
41
Treatment Tech Violations
1

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 28 2007
Coliform (TCR) MCL 20 2007
Nitrate MCL 5 1991
Chlorine MR 4 2007
TTHM MR 3 2020
Lead and Copper Rule MR 3 2020
Gross Alpha, Excl. Radon and U MR 2 1981
Coliform (TCR) Other 2 2005
Public Notice Other 2 2007
Consumer Confidence Rule Other 2 2021
LEAD AND COPPER RULE REVISIONS RPT 1 2024
LEAD AND COPPER RULE REVISIONS TT 1 2024
Total Haloacetic Acids (HAA5) MR 1 2005

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 SAN JUSTO MUTUAL WATER COMPANY.

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 CA3500550 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 SAN JUSTO MUTUAL WATER COMPANY 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 LEAD AND COPPER RULE REVISIONS RPT 1 SDWIS / CA3500550 / 5200
2024 LEAD AND COPPER RULE REVISIONS TT 1 SDWIS / CA3500550 / 5200
2021 Consumer Confidence Rule Other 2 SDWIS / CA3500550 / 7000
2020 TTHM MR 3 SDWIS / CA3500550 / 2950
2020 Lead and Copper Rule MR 3 SDWIS / CA3500550 / 5000
2007 Coliform (TCR) MR 28 SDWIS / CA3500550 / 3100
2007 Coliform (TCR) MCL 20 SDWIS / CA3500550 / 3100
2007 Chlorine MR 4 SDWIS / CA3500550 / 0999
2007 Public Notice Other 2 SDWIS / CA3500550 / 7500
2005 Coliform (TCR) Other 2 SDWIS / CA3500550 / 3100
2005 Total Haloacetic Acids (HAA5) MR 1 SDWIS / CA3500550 / 2456
1991 Nitrate MCL 5 SDWIS / CA3500550 / 1040
1981 Gross Alpha, Excl. Radon and U MR 2 SDWIS / CA3500550 / 4000

How SAN JUSTO MUTUAL WATER COMPANY Compares

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

Metric SAN JUSTO MUTUAL WATER COMPANY California avg Federal benchmark
Total violations 74 21.1 SDWA compliance — any non-zero count is a recorded breach
Health-based violations 26 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 160 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
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is SAN JUSTO MUTUAL WATER COMPANY water safe to drink?
SAN JUSTO MUTUAL WATER COMPANY (PWS ID: CA3500550) has 74 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 160 people using Groundwater sources.
How many people does SAN JUSTO MUTUAL WATER COMPANY serve?
SAN JUSTO MUTUAL WATER COMPANY serves 160 people in HOLLISTER, California. It is a Private-owned system using Groundwater water sources with 61 service connections.
What type of violations does SAN JUSTO MUTUAL WATER COMPANY have?
SAN JUSTO MUTUAL WATER COMPANY has 74 total violations: 26 health-based violations (MCL exceedances or treatment failures), 41 monitoring/reporting violations, and 1 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in SAN JUSTO MUTUAL WATER COMPANY water?
No PFAS testing data is available for SAN JUSTO MUTUAL WATER COMPANY under the EPA's UCMR5 monitoring program.
What water source does SAN JUSTO MUTUAL WATER COMPANY use?
SAN JUSTO MUTUAL WATER COMPANY uses Groundwater 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.

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Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. This data is provided for informational purposes only.

Related

Data sourced from $official public datasets. See our methodology for details. Retrieved and formatted by PlainWater Editorial