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WILLITS, CITY OF

PWS ID: CA2310004 · WILLITS, California 95490

WILLITS, CITY OF serves 6,175 people in WILLITS, California using Surface Water water sources. It has 28 recorded EPA violations, including 26 health-based violations. No PFAS contamination was detected in UCMR5 testing.

Water Quality Snapshot: WILLITS, CITY OF

WILLITS, CITY OF is a local-owned community water system that delivers drinking water to 6,175 residents in WILLITS, California (Mendocino County) through 2,399 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 28 total violations for this system , of which 26 (93%) are health-based — meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 2 monitoring and reporting violations are on file. The most recent violation on record dates to 2015.

The most frequently cited contaminant at this system is TTHM, recorded in 14 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. WILLITS, CITY OF's 28 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
6,175
Total Violations
28
Health-Based Violations
26
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
2,399
County
Mendocino
School/Daycare
No
MCL Violations
20
Monitoring Violations
2
Treatment Tech Violations
6

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
TTHM MCL 14 2015
Interim Enhanced Surface Water Treatment Rule TT 6 2012
Total Haloacetic Acids (HAA5) MCL 4 2013
Coliform (TCR) MR 2 2011
Coliform (TCR) MCL 2 1992

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 120 samples detected PFAS.

Contaminant Date Result MRL Status
ADONA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFHpS 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
4:2 FTS 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
HFPO-DA 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFBA 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
6:2 FTS 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
8:2 FTS 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFMPA 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFMBA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFPeS 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
9Cl-PF3ONS 7/26/2023 <0.002 µg/L 0.002 µg/L Not Detected
NFDHA 7/26/2023 <0.02 µg/L 0.02 µg/L Not Detected
11Cl-PF3OUdS 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFUnA 7/26/2023 <0.002 µg/L 0.002 µg/L Not Detected
PFHxA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFDoA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFDA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFOA 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFOS 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFNA 7/26/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFHxS 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFHpA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFBS 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFTrDA 7/26/2023 <0.007 µg/L 0.007 µg/L Not Detected
PFTA 7/26/2023 <0.008 µg/L 0.008 µg/L Not Detected
PFEESA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
lithium 7/26/2023 <9 µg/L 9 µg/L Not Detected
PFPeA 7/26/2023 <0.003 µg/L 0.003 µg/L Not Detected
NEtFOSAA 7/26/2023 <0.005 µg/L 0.005 µg/L Not Detected
NMeFOSAA 7/26/2023 <0.006 µg/L 0.006 µg/L Not Detected
lithium 4/5/2023 <9 µg/L 9 µg/L Not Detected
PFBS 4/5/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFOA 4/5/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFHxS 4/5/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFHpS 4/5/2023 <0.003 µg/L 0.003 µg/L Not Detected
NMeFOSAA 4/5/2023 <0.006 µg/L 0.006 µg/L Not Detected
NEtFOSAA 4/5/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFTrDA 4/5/2023 <0.007 µg/L 0.007 µg/L Not Detected
PFTA 4/5/2023 <0.008 µg/L 0.008 µg/L Not Detected
PFOS 4/5/2023 <0.004 µg/L 0.004 µg/L Not Detected
PFHpA 4/5/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFDA 4/5/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFDoA 4/5/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFHxA 4/5/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFUnA 4/5/2023 <0.002 µg/L 0.002 µg/L Not Detected
11Cl-PF3OUdS 4/5/2023 <0.005 µg/L 0.005 µg/L Not Detected
PFPeA 4/5/2023 <0.003 µg/L 0.003 µg/L Not Detected
PFPeS 4/5/2023 <0.004 µg/L 0.004 µg/L Not Detected
NFDHA 4/5/2023 <0.02 µg/L 0.02 µg/L Not Detected
PFNA 4/5/2023 <0.004 µg/L 0.004 µg/L 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 WILLITS, 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 CA2310004 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 WILLITS, 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
2015 TTHM MCL 14 SDWIS / CA2310004 / 2950
2013 Total Haloacetic Acids (HAA5) MCL 4 SDWIS / CA2310004 / 2456
2012 Interim Enhanced Surface Water Treatment Rule TT 6 SDWIS / CA2310004 / 0300
2011 Coliform (TCR) MR 2 SDWIS / CA2310004 / 3100
1992 Coliform (TCR) MCL 2 SDWIS / CA2310004 / 3100

How WILLITS, CITY OF Compares

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

Metric WILLITS, CITY OF California avg Federal benchmark
Total violations 28 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 6,175 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 WILLITS, CITY OF water safe to drink? ▼
WILLITS, CITY OF (PWS ID: CA2310004) has 28 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 6,175 people using Surface Water sources.
How many people does WILLITS, CITY OF serve? ▼
WILLITS, CITY OF serves 6,175 people in WILLITS, California. It is a Local-owned system using Surface Water water sources with 2,399 service connections.
What type of violations does WILLITS, CITY OF have? ▼
WILLITS, CITY OF has 28 total violations: 26 health-based violations (MCL exceedances or treatment failures), 2 monitoring/reporting violations, and 6 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in WILLITS, CITY OF water? ▼
No. WILLITS, CITY OF was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does WILLITS, CITY OF use? ▼
WILLITS, 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.

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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.

Read our methodology — how this data is sourced, computed, and verified.

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