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Community Water System · PWS CA4410001

Big Basin Water Company

Irvine, California 92606 - drinking water served from groundwater sources to 1,120 people, tracked in EPA SDWIS and UCMR5.

1,120
People served
102
EPA violations
52
Health-based
Untested
UCMR5 result

The verdict

EPA records 102 drinking-water violations at Big Basin Water Company, 51% of them health-based - above the California per-system average.

102
Total EPA violations on record
51%
Health-based (MCL / treatment failure)
1,120
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Big Basin Water Company

Big Basin Water Company is a private-owned community water system that delivers drinking water to 1,120 residents in Irvine, California (Santa Cruz County) through 540 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 102 total violations for this system , of which 52 (51%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 47 monitoring and reporting violations are on file. The most recent violation on record dates to 2022.

The most frequently cited contaminant at this system is Interim Enhanced Surface Water Treatment Rule, recorded in 52 violations (TT, health-based). 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. Statewide, 447 of 694 UCMR5-tested systems have reported PFAS detections (64.4%).

Big Basin Water Company's 102 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.

Population Served
1,120
Total Violations
102
Health-Based Violations
52
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Private
Connections
540
County
Santa Cruz
School/Daycare
No
MCL Violations
0
Monitoring Violations
47
Treatment Tech Violations
52

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Interim Enhanced Surface Water Treatment Rule TT 52 2005
TTHM MR 12 2022
Total Haloacetic Acids (HAA5) MR 12 2022
Coliform (TCR) MR 5 2004
Nitrate MR 4 2018
Revised Total Coliform Rule MON 4 2022
Chlorine MR 2 2005
Simazine MR 2 2018
Arsenic MR 2 2018
Nitrite MR 2 2018
Lead and Copper Rule MR 2 1993

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 Big Basin 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 CA4410001 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 Big Basin 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
2022 TTHM MR 12 SDWIS / CA4410001 / 2950
2022 Total Haloacetic Acids (HAA5) MR 12 SDWIS / CA4410001 / 2456
2022 Revised Total Coliform Rule MON 4 SDWIS / CA4410001 / 8000
2018 Nitrate MR 4 SDWIS / CA4410001 / 1040
2018 Simazine MR 2 SDWIS / CA4410001 / 2037
2018 Arsenic MR 2 SDWIS / CA4410001 / 1005
2018 Nitrite MR 2 SDWIS / CA4410001 / 1041
2005 Interim Enhanced Surface Water Treatment Rule TT 52 SDWIS / CA4410001 / 0300
2005 Chlorine MR 2 SDWIS / CA4410001 / 0999
2004 Coliform (TCR) MR 5 SDWIS / CA4410001 / 3100
1993 Lead and Copper Rule MR 2 SDWIS / CA4410001 / 5000

How Big Basin Water Company Compares

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

Metric Big Basin Water Company California avg Federal benchmark
Total violations 102 21.1 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 52 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 1,120 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 Big Basin Water Company water safe to drink? ▼
Big Basin Water Company (PWS ID: CA4410001) has 102 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 1,120 people using Groundwater sources.
How many people does Big Basin Water Company serve? ▼
Big Basin Water Company serves 1,120 people in Irvine, California. It is a Private-owned system using Groundwater water sources with 540 service connections.
What type of violations does Big Basin Water Company have? ▼
Big Basin Water Company has 102 total violations: 52 health-based violations (MCL exceedances or treatment failures), 47 monitoring/reporting violations, and 52 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Big Basin Water Company water? ▼
No PFAS testing data is available for Big Basin Water Company under the EPA's UCMR5 monitoring program.
What water source does Big Basin Water Company use? ▼
Big Basin 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.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 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.