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Community Water System · PWS CA1910070

Los Angeles Cwwd 40 Reg 4 & 34 Lancaster

Alhambra, California 91803 - drinking water served from surface water sources to 208,129 people, tracked in EPA SDWIS and UCMR5.

208,129
People served
11
EPA violations
2
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 11 drinking-water violations at Los Angeles Cwwd 40 Reg 4 & 34 Lancaster, 18% of them health-based - below the California per-system average.

11
Total EPA violations on record
18%
Health-based (MCL / treatment failure)
208,129
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Los Angeles Cwwd 40 Reg 4 & 34 Lancaster

Los Angeles Cwwd 40 Reg 4 & 34 Lancaster is a local-owned community water system that delivers drinking water to 208,129 residents in Alhambra, California (Los Angeles County) through 52,956 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 11 total violations for this system , of which 2 (18%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 6 monitoring and reporting violations are on file. The most recent violation on record dates to 2007.

The most frequently cited contaminant at this system is Nitrite, recorded in 2 violations (MR). 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%).

Los Angeles Cwwd 40 Reg 4 & 34 Lancaster's 11 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.

Population Served
208,129
Total Violations
11
Health-Based Violations
2
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
52,956
County
Los Angeles
School/Daycare
No
MCL Violations
2
Monitoring Violations
6
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Nitrite MR 2 2003
Arsenic MR 2 2007
Coliform (TCR) MCL 2 1992
Nitrate MR 2 2003

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 812 samples detected PFAS.

Contaminant Date Result MRL Status
6:2 FTS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFMPA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFMBA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
NFDHA 9/12/2023 <20.00 ppt 20.00 ppt Not Detected
PFPeS 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFHpS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFBS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFBA 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFPeA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
ADONA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFTrDA 9/12/2023 <7.00 ppt 7.00 ppt Not Detected
PFEESA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 9/12/2023 <2.00 ppt 2.00 ppt Not Detected
PFTA 9/12/2023 <8.00 ppt 8.00 ppt Not Detected
NEtFOSAA 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 9/12/2023 <6.00 ppt 6.00 ppt Not Detected
PFHxS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFOS 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFOA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFDA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFDoA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFNA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFUnA 9/12/2023 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFOA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
HFPO-DA 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
ADONA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 9/12/2023 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFUnA 9/12/2023 <2.00 ppt 2.00 ppt Not Detected
PFHxA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFNA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFDA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFOS 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFBA 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFTA 9/12/2023 <8.00 ppt 8.00 ppt Not Detected
PFDoA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
6:2 FTS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 9/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFMPA 9/12/2023 <4.00 ppt 4.00 ppt Not Detected
PFPeA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFMBA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFEESA 9/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFTrDA 9/12/2023 <7.00 ppt 7.00 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 Los Angeles Cwwd 40 Reg 4 & 34 Lancaster.

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 CA1910070 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 Los Angeles Cwwd 40 Reg 4 & 34 Lancaster 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
2007 Arsenic MR 2 SDWIS / CA1910070 / 1005
2003 Nitrite MR 2 SDWIS / CA1910070 / 1041
2003 Nitrate MR 2 SDWIS / CA1910070 / 1040
1992 Coliform (TCR) MCL 2 SDWIS / CA1910070 / 3100

How Los Angeles Cwwd 40 Reg 4 & 34 Lancaster Compares

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

Metric Los Angeles Cwwd 40 Reg 4 & 34 Lancaster California avg Federal benchmark
Total violations 11 21.1 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 2 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 208,129 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 Los Angeles Cwwd 40 Reg 4 & 34 Lancaster water safe to drink? ▼
Los Angeles Cwwd 40 Reg 4 & 34 Lancaster (PWS ID: CA1910070) has 11 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 208,129 people using Surface Water sources.
How many people does Los Angeles Cwwd 40 Reg 4 & 34 Lancaster serve? ▼
Los Angeles Cwwd 40 Reg 4 & 34 Lancaster serves 208,129 people in Alhambra, California. It is a Local-owned system using Surface Water water sources with 52,956 service connections.
What type of violations does Los Angeles Cwwd 40 Reg 4 & 34 Lancaster have? ▼
Los Angeles Cwwd 40 Reg 4 & 34 Lancaster has 11 total violations: 2 health-based violations (MCL exceedances or treatment failures), 6 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Los Angeles Cwwd 40 Reg 4 & 34 Lancaster water? ▼
No. Los Angeles Cwwd 40 Reg 4 & 34 Lancaster was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does Los Angeles Cwwd 40 Reg 4 & 34 Lancaster use? ▼
Los Angeles Cwwd 40 Reg 4 & 34 Lancaster 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.

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

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.