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Community Water System · PWS CA3310036

Western MWD - Murrieta Division

Riverside, California 92503 - drinking water served from surface water sources to 17,453 people, tracked in EPA SDWIS and UCMR5.

17,453
People served
14
EPA violations
4
Health-based
3 PFAS
UCMR5 result

The verdict

EPA records 14 drinking-water violations at Western MWD - Murrieta Division, 29% of them health-based - below the California per-system average, and UCMR5 testing detected 3 PFAS compounds.

14
Total EPA violations on record
29%
Health-based (MCL / treatment failure)
17,453
People served by this system
3
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Western MWD - Murrieta Division

Western MWD - Murrieta Division is a local-owned community water system that delivers drinking water to 17,453 residents in Riverside, California (Riverside County) through 2,868 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 14 total violations for this system , of which 4 (29%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 10 monitoring and reporting violations are on file. The most recent violation on record dates to 2006.

The most frequently cited contaminant at this system is Nitrate, recorded in 6 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 5.7 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%).

Western MWD - Murrieta Division's 14 violations sit below 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
17,453
Total Violations
14
Health-Based Violations
4
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
2,868
County
Riverside
School/Daycare
No
MCL Violations
4
Monitoring Violations
10
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Nitrate MR 6 2005
Coliform (TCR) MR 2 2004
Lead and Copper Rule MR 2 1993
Coliform (TCR) MCL 2 1994
Nitrate MCL 2 2006

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 6 of 232 samples detected PFAS.

Contaminant Date Result MRL Status
9Cl-PF3ONS 8/26/2024 <2.00 ppt 2.00 ppt Not Detected
PFHpA 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
PFDA 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
PFUnA 8/26/2024 <2.00 ppt 2.00 ppt Not Detected
PFHxA 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
PFDoA 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
11Cl-PF3OUdS 8/26/2024 <5.00 ppt 5.00 ppt Not Detected
PFOA 8/26/2024 4.70 ppt 4.00 ppt Detected
PFOS 8/26/2024 4.10 ppt 4.00 ppt Detected
PFHxS 8/26/2024 3.00 ppt 3.00 ppt Detected
PFTA 8/26/2024 <8.00 ppt 8.00 ppt Not Detected
PFBS 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
ADONA 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
PFMPA 8/26/2024 <4.00 ppt 4.00 ppt Not Detected
PFNA 8/26/2024 <4.00 ppt 4.00 ppt Not Detected
NEtFOSAA 8/26/2024 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
PFTrDA 8/26/2024 <7.00 ppt 7.00 ppt Not Detected
HFPO-DA 8/26/2024 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 8/26/2024 <6.00 ppt 6.00 ppt Not Detected
PFHpS 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeS 8/26/2024 <4.00 ppt 4.00 ppt Not Detected
PFEESA 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
PFMBA 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeA 8/26/2024 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 8/26/2024 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 8/26/2024 <5.00 ppt 5.00 ppt Not Detected
PFBA 8/26/2024 <5.00 ppt 5.00 ppt Not Detected
NFDHA 8/26/2024 <20.00 ppt 20.00 ppt Not Detected
PFDA 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
NMeFOSAA 8/11/2023 <6.00 ppt 6.00 ppt Not Detected
PFTA 8/11/2023 <8.00 ppt 8.00 ppt Not Detected
PFTrDA 8/11/2023 <7.00 ppt 7.00 ppt Not Detected
NEtFOSAA 8/11/2023 <5.00 ppt 5.00 ppt Not Detected
PFOA 8/11/2023 <4.00 ppt 4.00 ppt Not Detected
PFOS 8/11/2023 <4.00 ppt 4.00 ppt Not Detected
11Cl-PF3OUdS 8/11/2023 <5.00 ppt 5.00 ppt Not Detected
PFUnA 8/11/2023 <2.00 ppt 2.00 ppt Not Detected
PFDoA 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpS 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeS 8/11/2023 <4.00 ppt 4.00 ppt Not Detected
NFDHA 8/11/2023 <20.00 ppt 20.00 ppt Not Detected
PFEESA 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxS 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
PFBS 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxA 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
PFMBA 8/11/2023 <3.00 ppt 3.00 ppt Not Detected
PFNA 8/11/2023 <4.00 ppt 4.00 ppt Not Detected
9Cl-PF3ONS 8/11/2023 <2.00 ppt 2.00 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 Western MWD - Murrieta Division.

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 CA3310036 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 Western MWD - Murrieta Division 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
2006 Nitrate MCL 2 SDWIS / CA3310036 / 1040
2005 Nitrate MR 6 SDWIS / CA3310036 / 1040
2004 Coliform (TCR) MR 2 SDWIS / CA3310036 / 3100
1994 Coliform (TCR) MCL 2 SDWIS / CA3310036 / 3100
1993 Lead and Copper Rule MR 2 SDWIS / CA3310036 / 5000

How Western MWD - Murrieta Division Compares

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

Metric Western MWD - Murrieta Division California avg Federal benchmark
Total violations 14 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 17,453 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 Western MWD - Murrieta Division water safe to drink?
Western MWD - Murrieta Division (PWS ID: CA3310036) has 14 recorded violations in the EPA SDWIS database. PFAS contamination has been detected in UCMR5 testing, with 3 PFAS compounds found. This system serves 17,453 people using Surface Water sources.
How many people does Western MWD - Murrieta Division serve?
Western MWD - Murrieta Division serves 17,453 people in Riverside, California. It is a Local-owned system using Surface Water water sources with 2,868 service connections.
What type of violations does Western MWD - Murrieta Division have?
Western MWD - Murrieta Division has 14 total violations: 4 health-based violations (MCL exceedances or treatment failures), 10 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Western MWD - Murrieta Division water?
Yes. UCMR5 testing detected 3 PFAS compounds in Western MWD - Murrieta Division's water supply: PFOA, PFOS, PFHxS. PFAS are persistent "forever chemicals" that do not break down in the environment.
What water source does Western MWD - Murrieta Division use?
Western MWD - Murrieta Division 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.