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States → Navajo Nation

Community Water System · PWS NN3500269

White Rock-Lake Valley NTUA

Ft Defiance, Navajo Nation 86504 - drinking water served from groundwater sources to 492 people, tracked in EPA SDWIS and UCMR5.

492
People served
220
EPA violations
12
Health-based
Untested
UCMR5 result

The verdict

EPA records 220 drinking-water violations at White Rock-Lake Valley NTUA, 5% of them health-based - above the Navajo Nation per-system average.

220
Total EPA violations on record
5%
Health-based (MCL / treatment failure)
492
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: White Rock-Lake Valley NTUA

White Rock-Lake Valley NTUA is a native american-owned community water system that delivers drinking water to 492 residents in Ft Defiance, Navajo Nation through 144 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 220 total violations for this system , of which 12 (5%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 177 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 12 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.

Across Navajo Nation, EPA tracks 170 public water systems serving 167,275 people, with 29,535 cumulative violations and 1,366 health-based violations on record. About 100% of systems in the state carry at least one violation, and state-wide the average per system is 173.7 violations. Statewide, 13 of 13 UCMR5-tested systems have reported PFAS detections (100%).

White Rock-Lake Valley NTUA's 220 violations sit above the Navajo Nation 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
492
Total Violations
220
Health-Based Violations
12
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Native American
Connections
144
School/Daycare
No
MCL Violations
12
Monitoring Violations
177
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MCL 12 2012
Coliform (TCR) MR 11 2012
Arsenic MR 9 2024
ETHYLENE DIBROMIDE MR 8 2011
1,2-DIBROMO-3-CHLOROPROPANE MR 8 2011
Mercury MR 7 2011
Antimony, Total MR 7 2011
Thallium, Total MR 7 2011
DICHLOROMETHANE MR 7 2011
trans-1,2-Dichloroethylene MR 7 2011
Chromium MR 4 2011
Beryllium, Total MR 4 2011
1,2,4-Trichlorobenzene MR 4 2011
cis-1,2-Dichloroethylene MR 4 2011
Xylenes, Total MR 4 2011
o-Dichlorobenzene MR 4 2011
Vinyl chloride MR 4 2011
1,1-Dichloroethylene MR 4 2011
1,2-Dichloroethane MR 4 2011
Trichloroethylene MR 4 2011
1,1,2-Trichloroethane MR 4 2011
Benzene MR 4 2011
Toluene MR 4 2011
Styrene MR 4 2011
p-Dichlorobenzene MR 4 2011
Barium MR 4 2011
Carbon tetrachloride MR 4 2011
Selenium MR 4 2011
1,2-Dichloropropane MR 4 2011
Fluoride MR 4 2011

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 White Rock-Lake Valley NTUA.

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 NN3500269 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Navajo Nation Drinking Water Authority

Navajo Nation'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 NN 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
2024 Arsenic MR 9 SDWIS / NN3500269 / 1005
2016 Revised Total Coliform Rule Other 1 SDWIS / NN3500269 / 8000
2012 Coliform (TCR) MCL 12 SDWIS / NN3500269 / 3100
2012 Coliform (TCR) MR 11 SDWIS / NN3500269 / 3100
2011 ETHYLENE DIBROMIDE MR 8 SDWIS / NN3500269 / 2946
2011 1,2-DIBROMO-3-CHLOROPROPANE MR 8 SDWIS / NN3500269 / 2931
2011 Mercury MR 7 SDWIS / NN3500269 / 1035
2011 Antimony, Total MR 7 SDWIS / NN3500269 / 1074
2011 Thallium, Total MR 7 SDWIS / NN3500269 / 1085
2011 DICHLOROMETHANE MR 7 SDWIS / NN3500269 / 2964
2011 trans-1,2-Dichloroethylene MR 7 SDWIS / NN3500269 / 2979
2011 Chromium MR 4 SDWIS / NN3500269 / 1020
2011 Beryllium, Total MR 4 SDWIS / NN3500269 / 1075
2011 1,2,4-Trichlorobenzene MR 4 SDWIS / NN3500269 / 2378
2011 cis-1,2-Dichloroethylene MR 4 SDWIS / NN3500269 / 2380

How White Rock-Lake Valley NTUA Compares

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

Metric White Rock-Lake Valley NTUA Navajo Nation avg Federal benchmark
Total violations 220 173.7 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 12 8 Indicates a contaminant exceeded a federal MCL
PFAS detection None 100% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 492 984 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 170 regulated public water systems in Navajo Nation.

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 White Rock-Lake Valley NTUA water safe to drink? ▼
White Rock-Lake Valley NTUA (PWS ID: NN3500269) has 220 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 492 people using Groundwater sources.
How many people does White Rock-Lake Valley NTUA serve? ▼
White Rock-Lake Valley NTUA serves 492 people in Ft Defiance, Navajo Nation. It is a Native American-owned system using Groundwater water sources with 144 service connections.
What type of violations does White Rock-Lake Valley NTUA have? ▼
White Rock-Lake Valley NTUA has 220 total violations: 12 health-based violations (MCL exceedances or treatment failures), 177 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in White Rock-Lake Valley NTUA water? ▼
No PFAS testing data is available for White Rock-Lake Valley NTUA under the EPA's UCMR5 monitoring program.
What water source does White Rock-Lake Valley NTUA use? ▼
White Rock-Lake Valley NTUA 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.