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Community Water System · PWS NN0400825

Long House Valley NTUA

Ft Defiance, Navajo Nation 86504 - drinking water served from groundwater sources to 277 people, tracked in EPA SDWIS and UCMR5.

277
People served
33
EPA violations
0
Health-based
Untested
UCMR5 result

The verdict

EPA records 33 drinking-water violations at Long House Valley NTUA - below the Navajo Nation per-system average.

33
Total EPA violations on record
0%
Health-based (MCL / treatment failure)
277
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Long House Valley NTUA

Long House Valley NTUA is a native american-owned community water system that delivers drinking water to 277 residents in Ft Defiance, Navajo Nation through 81 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 33 total violations for this system , of which 0 (0%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 32 monitoring and reporting violations are on file. The most recent violation on record dates to 2020.

The most frequently cited contaminant at this system is Total Haloacetic Acids (HAA5), recorded in 14 violations (MR). 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%).

Long House Valley NTUA's 33 violations sit below 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
277
Total Violations
33
Health-Based Violations
0
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Native American
Connections
81
School/Daycare
No
MCL Violations
0
Monitoring Violations
32
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Total Haloacetic Acids (HAA5) MR 14 2020
TTHM MR 14 2020
Lead and Copper Rule MR 3 2020
Revised Total Coliform Rule Other 1 2016
Stage 2 Disinfectants and Disinfection Byproducts Rule MR 1 2013

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 Long House 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 NN0400825 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
2020 Total Haloacetic Acids (HAA5) MR 14 SDWIS / NN0400825 / 2456
2020 TTHM MR 14 SDWIS / NN0400825 / 2950
2020 Lead and Copper Rule MR 3 SDWIS / NN0400825 / 5000
2016 Revised Total Coliform Rule Other 1 SDWIS / NN0400825 / 8000
2013 Stage 2 Disinfectants and Disinfection Byproducts Rule MR 1 SDWIS / NN0400825 / 0600

How Long House Valley NTUA Compares

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

Metric Long House Valley NTUA Navajo Nation avg Federal benchmark
Total violations 33 173.7 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 0 8 Indicates a contaminant exceeded a federal MCL
PFAS detection None 100% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 277 984 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 Long House Valley NTUA water safe to drink? ▼
Long House Valley NTUA (PWS ID: NN0400825) has 33 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 277 people using Groundwater sources.
How many people does Long House Valley NTUA serve? ▼
Long House Valley NTUA serves 277 people in Ft Defiance, Navajo Nation. It is a Native American-owned system using Groundwater water sources with 81 service connections.
What type of violations does Long House Valley NTUA have? ▼
Long House Valley NTUA has 33 total violations: 0 health-based violations (MCL exceedances or treatment failures), 32 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Long House Valley NTUA water? ▼
No PFAS testing data is available for Long House Valley NTUA under the EPA's UCMR5 monitoring program.
What water source does Long House Valley NTUA use? ▼
Long House 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.