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Community Water System · PWS CA4910014

Rohnert Park, City Of

Rohnert Park, California 94928 - drinking water served from groundwater sources to 43,821 people, tracked in EPA SDWIS and UCMR5.

43,821
People served
561
EPA violations
4
Health-based
3 PFAS
UCMR5 result

The verdict

EPA records 561 drinking-water violations at Rohnert Park, City Of, 1% of them health-based - above the California per-system average, and UCMR5 testing detected 3 PFAS compounds.

561
Total EPA violations on record
1%
Health-based (MCL / treatment failure)
43,821
People served by this system
3
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Rohnert Park, City Of

Rohnert Park, City Of is a local-owned community water system that delivers drinking water to 43,821 residents in Rohnert Park, California (Sonoma County) through 10,427 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 561 total violations for this system , of which 4 (1%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 552 monitoring and reporting violations are on file. The most recent violation on record dates to 2021.

The most frequently cited contaminant at this system is p-Dichlorobenzene, recorded in 26 violations (MR). Under EPA's UCMR5 PFAS monitoring program, 3 PFAS compounds were detected in samples collected from this system, with a maximum reported concentration of 7.1 ppt (parts per trillion). PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.

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%).

Rohnert Park, City Of's 561 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.

PFAS Detected

3 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.

Population Served
43,821
Total Violations
561
Health-Based Violations
4
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
10,427
County
Sonoma
School/Daycare
No
MCL Violations
4
Monitoring Violations
552
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
p-Dichlorobenzene MR 26 2017
Vinyl chloride MR 26 2017
1,1-Dichloroethylene MR 26 2017
trans-1,2-Dichloroethylene MR 26 2017
1,2-Dichloroethane MR 26 2017
1,1,1-Trichloroethane MR 26 2017
1,2-Dichloropropane MR 26 2017
1,1,2-Trichloroethane MR 26 2017
Tetrachloroethylene MR 26 2017
Benzene MR 26 2017
Toluene MR 26 2017
1,2,4-Trichlorobenzene MR 26 2017
cis-1,2-Dichloroethylene MR 26 2017
DICHLOROMETHANE MR 26 2017
o-Dichlorobenzene MR 26 2017
Carbon tetrachloride MR 26 2017
Ethylbenzene MR 26 2017
Styrene MR 26 2017
Xylenes, Total MR 26 2017
Trichloroethylene MR 26 2017
CHLOROBENZENE MR 26 2017
Coliform (TCR) MCL 4 2011
Revised Total Coliform Rule MON 2 2021
Arsenic MR 2 2021
Nitrate MR 2 2017

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 4 of 464 samples detected PFAS.

Contaminant Date Result MRL Status
PFHpA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
ADONA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 5/21/2024 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
PFUnA 5/21/2024 <2.00 ppt 2.00 ppt Not Detected
PFHxA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFDoA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFDA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFOA 5/21/2024 <4.00 ppt 4.00 ppt Not Detected
PFOS 5/21/2024 <4.00 ppt 4.00 ppt Not Detected
PFHxS 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFBS 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
PFHpS 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFNA 5/21/2024 <4.00 ppt 4.00 ppt Not Detected
PFPeS 5/21/2024 <4.00 ppt 4.00 ppt Not Detected
6:2 FTS 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
PFMPA 5/21/2024 <4.00 ppt 4.00 ppt Not Detected
PFPeA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFMBA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFEESA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFTrDA 5/21/2024 <7.00 ppt 7.00 ppt Not Detected
PFBA 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 5/21/2024 <6.00 ppt 6.00 ppt Not Detected
NEtFOSAA 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
PFTA 5/21/2024 <8.00 ppt 8.00 ppt Not Detected
NFDHA 5/21/2024 <20.00 ppt 20.00 ppt Not Detected
PFTA 5/21/2024 <8.00 ppt 8.00 ppt Not Detected
PFTrDA 5/21/2024 <7.00 ppt 7.00 ppt Not Detected
NEtFOSAA 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 5/21/2024 <6.00 ppt 6.00 ppt Not Detected
8:2 FTS 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
PFUnA 5/21/2024 <2.00 ppt 2.00 ppt Not Detected
PFOA 5/21/2024 <4.00 ppt 4.00 ppt Not Detected
PFBS 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFHpA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxS 5/21/2024 3.60 ppt 3.00 ppt Detected
PFOS 5/21/2024 <4.00 ppt 4.00 ppt Not Detected
PFDA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
PFHpS 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
11Cl-PF3OUdS 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
9Cl-PF3ONS 5/21/2024 <2.00 ppt 2.00 ppt Not Detected
ADONA 5/21/2024 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
PFBA 5/21/2024 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 5/21/2024 <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 Rohnert Park, 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 CA4910014 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 Rohnert Park, 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
2021 Revised Total Coliform Rule MON 2 SDWIS / CA4910014 / 8000
2021 Arsenic MR 2 SDWIS / CA4910014 / 1005
2017 p-Dichlorobenzene MR 26 SDWIS / CA4910014 / 2969
2017 Vinyl chloride MR 26 SDWIS / CA4910014 / 2976
2017 1,1-Dichloroethylene MR 26 SDWIS / CA4910014 / 2977
2017 trans-1,2-Dichloroethylene MR 26 SDWIS / CA4910014 / 2979
2017 1,2-Dichloroethane MR 26 SDWIS / CA4910014 / 2980
2017 1,1,1-Trichloroethane MR 26 SDWIS / CA4910014 / 2981
2017 1,2-Dichloropropane MR 26 SDWIS / CA4910014 / 2983
2017 1,1,2-Trichloroethane MR 26 SDWIS / CA4910014 / 2985
2017 Tetrachloroethylene MR 26 SDWIS / CA4910014 / 2987
2017 Benzene MR 26 SDWIS / CA4910014 / 2990
2017 Toluene MR 26 SDWIS / CA4910014 / 2991
2017 1,2,4-Trichlorobenzene MR 26 SDWIS / CA4910014 / 2378
2017 cis-1,2-Dichloroethylene MR 26 SDWIS / CA4910014 / 2380

How Rohnert Park, City Of Compares

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

Metric Rohnert Park, City Of California avg Federal benchmark
Total violations 561 21.1 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 4 8.8 Indicates a contaminant exceeded a federal MCL
PFAS detection 3 compounds 64.4% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 43,821 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 Rohnert Park, City Of water safe to drink?
Rohnert Park, City Of (PWS ID: CA4910014) has 561 recorded violations in the EPA SDWIS database. PFAS contamination has been detected in UCMR5 testing, with 3 PFAS compounds found. This system serves 43,821 people using Groundwater sources.
How many people does Rohnert Park, City Of serve?
Rohnert Park, City Of serves 43,821 people in Rohnert Park, California. It is a Local-owned system using Groundwater water sources with 10,427 service connections.
What type of violations does Rohnert Park, City Of have?
Rohnert Park, City Of has 561 total violations: 4 health-based violations (MCL exceedances or treatment failures), 552 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Rohnert Park, City Of water?
Yes. UCMR5 testing detected 3 PFAS compounds in Rohnert Park, City Of's water supply: PFHxS, 6:2 FTS, PFOS. PFAS are persistent "forever chemicals" that do not break down in the environment.
What water source does Rohnert Park, City Of use?
Rohnert Park, City Of 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.
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.