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States → EPA Region 9 — Tribal Water Systems

Community Water System · PWS 090600121

Big Sandy Rancheria

Auberry, EPA Region 9 — Tribal Water Systems 93602 - drinking water served from groundwater sources to 408 people, tracked in EPA SDWIS and UCMR5.

408
People served
425
EPA violations
56
Health-based
Untested
UCMR5 result

The verdict

EPA records 425 drinking-water violations at Big Sandy Rancheria, 13% of them health-based.

425
Total EPA violations on record
13%
Health-based (MCL / treatment failure)
408
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Big Sandy Rancheria

Big Sandy Rancheria is a native american-owned community water system that delivers drinking water to 408 residents in Auberry, EPA Region 9 — Tribal Water Systems through 62 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 425 total violations for this system , of which 56 (13%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 114 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.

The most frequently cited contaminant at this system is Combined Uranium, recorded in 47 violations (MCL, health-based). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

EPA Region 9 — Tribal Water Systems has thousands of regulated public water systems tracked by EPA under the Safe Drinking Water Act.

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
408
Total Violations
425
Health-Based Violations
56
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Native American
Connections
62
School/Daycare
No
MCL Violations
56
Monitoring Violations
114
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Combined Uranium MCL 47 2025
Coliform (TCR) MR 19 2014
Coliform (TCR) MCL 9 2013
Consumer Confidence Rule Other 6 2006
Public Notice Other 4 2025
Nitrate MR 3 2017
Chlorine MR 3 2024
E. COLI MR 3 2023
Lead and Copper Rule MR 3 1999
Mercury MR 2 2017
Carbofuran MR 2 2017
LASSO MR 2 2017
2,4-D MR 2 2017
2,4,5-TP MR 2 2017
Gross Alpha, Excl. Radon and U MR 2 2017
Combined Uranium MR 2 2023
Combined Radium (-226 and -228) MR 2 2017
Radium-226 MR 2 2001
Pentachlorophenol MR 2 2017
Total Haloacetic Acids (HAA5) MR 2 2023
Nitrite MR 2 2017
TTHM MR 2 2023
Arsenic MR 1 2017
Barium MR 1 2017
Cadmium MR 1 2017
Chromium MR 1 2017
Selenium MR 1 2017
Beryllium, Total MR 1 2017
Thallium, Total MR 1 2017
Endrin MR 1 2017

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 Sandy Rancheria.

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 090600121 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

EPA Region 9 — Tribal Water Systems Drinking Water Authority

EPA Region 9 — Tribal Water Systems's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.

Find 09 regulator via EPA SDWIS

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
2025 Combined Uranium MCL 47 SDWIS / 090600121 / 4006
2025 Public Notice Other 4 SDWIS / 090600121 / 7500
2024 Chlorine MR 3 SDWIS / 090600121 / 0999
2023 E. COLI MR 3 SDWIS / 090600121 / 3014
2023 Combined Uranium MR 2 SDWIS / 090600121 / 4006
2023 Total Haloacetic Acids (HAA5) MR 2 SDWIS / 090600121 / 2456
2023 TTHM MR 2 SDWIS / 090600121 / 2950
2023 Revised Total Coliform Rule MON 1 SDWIS / 090600121 / 8000
2017 Nitrate MR 3 SDWIS / 090600121 / 1040
2017 Mercury MR 2 SDWIS / 090600121 / 1035
2017 Carbofuran MR 2 SDWIS / 090600121 / 2046
2017 LASSO MR 2 SDWIS / 090600121 / 2051
2017 2,4-D MR 2 SDWIS / 090600121 / 2105
2017 2,4,5-TP MR 2 SDWIS / 090600121 / 2110
2017 Gross Alpha, Excl. Radon and U MR 2 SDWIS / 090600121 / 4000

How Big Sandy Rancheria Compares

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

Metric Big Sandy Rancheria EPA Region 9 — Tribal Water Systems avg Federal benchmark
Total violations 425 - SDWA compliance, any non-zero count is a recorded breach
Health-based violations 56 - Indicates a contaminant exceeded a federal MCL
PFAS detection None - EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 408 - Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across all regulated public water systems in EPA Region 9 — Tribal Water Systems.

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 Sandy Rancheria water safe to drink? ▼
Big Sandy Rancheria (PWS ID: 090600121) has 425 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 408 people using Groundwater sources.
How many people does Big Sandy Rancheria serve? ▼
Big Sandy Rancheria serves 408 people in Auberry, EPA Region 9 — Tribal Water Systems. It is a Native American-owned system using Groundwater water sources with 62 service connections.
What type of violations does Big Sandy Rancheria have? ▼
Big Sandy Rancheria has 425 total violations: 56 health-based violations (MCL exceedances or treatment failures), 114 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Big Sandy Rancheria water? ▼
No PFAS testing data is available for Big Sandy Rancheria under the EPA's UCMR5 monitoring program.
What water source does Big Sandy Rancheria use? ▼
Big Sandy Rancheria 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.