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Community Water System · PWS NN0400286

White Post Mission NTUA

Ft Defiance, Navajo Nation 86504 - drinking water served from groundwater sources to 185 people, tracked in EPA SDWIS and UCMR5.

185
People served
1,145
EPA violations
0
Health-based
Untested
UCMR5 result

The verdict

EPA records 1,145 drinking-water violations at White Post Mission NTUA - above the Navajo Nation per-system average.

1,145
Total EPA violations on record
0%
Health-based (MCL / treatment failure)
185
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: White Post Mission NTUA

White Post Mission NTUA is a native american-owned community water system that delivers drinking water to 185 residents in Ft Defiance, Navajo Nation through 54 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 1,145 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 1,044 monitoring and reporting violations are on file. The most recent violation on record dates to 2016.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 251 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%).

White Post Mission NTUA's 1,145 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
185
Total Violations
1,145
Health-Based Violations
0
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Native American
Connections
54
School/Daycare
No
MCL Violations
0
Monitoring Violations
1,044
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 251 2014
Nitrate MR 20 2016
Diquat MR 18 2014
Endothall MR 18 2014
Glyphosate MR 18 2014
2,3,7,8-TCDD MR 18 2014
Consumer Confidence Rule Other 16 2013
Nitrite MR 14 2016
Di(2-ethylhexyl) adipate MR 13 2014
2,4,5-TP MR 13 2014
trans-1,2-Dichloroethylene MR 13 2014
Endrin MR 12 2014
BHC-GAMMA MR 12 2014
Methoxychlor MR 12 2014
Toxaphene MR 12 2014
Dalapon MR 12 2014
OXAMYL MR 12 2014
Simazine MR 12 2014
Di(2-ethylhexyl) phthalate MR 12 2014
Picloram MR 12 2014
Dinoseb MR 12 2014
Hexachlorocyclopentadiene MR 12 2014
Carbofuran MR 12 2014
Atrazine MR 12 2014
LASSO MR 12 2014
Heptachlor MR 12 2014
Heptachlor epoxide MR 12 2014
2,4-D MR 12 2014
HEXACHLOROBENZENE MR 12 2014
Benzo(a)pyrene MR 12 2014

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 Post Mission 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 NN0400286 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
2016 Nitrate MR 20 SDWIS / NN0400286 / 1040
2016 Nitrite MR 14 SDWIS / NN0400286 / 1041
2014 Coliform (TCR) MR 251 SDWIS / NN0400286 / 3100
2014 Diquat MR 18 SDWIS / NN0400286 / 2032
2014 Endothall MR 18 SDWIS / NN0400286 / 2033
2014 Glyphosate MR 18 SDWIS / NN0400286 / 2034
2014 2,3,7,8-TCDD MR 18 SDWIS / NN0400286 / 2063
2014 Di(2-ethylhexyl) adipate MR 13 SDWIS / NN0400286 / 2035
2014 2,4,5-TP MR 13 SDWIS / NN0400286 / 2110
2014 trans-1,2-Dichloroethylene MR 13 SDWIS / NN0400286 / 2979
2014 Endrin MR 12 SDWIS / NN0400286 / 2005
2014 BHC-GAMMA MR 12 SDWIS / NN0400286 / 2010
2014 Methoxychlor MR 12 SDWIS / NN0400286 / 2015
2014 Toxaphene MR 12 SDWIS / NN0400286 / 2020
2014 Dalapon MR 12 SDWIS / NN0400286 / 2031

How White Post Mission NTUA Compares

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

Metric White Post Mission NTUA Navajo Nation avg Federal benchmark
Total violations 1,145 173.7 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 185 984 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 Post Mission NTUA water safe to drink? ▼
White Post Mission NTUA (PWS ID: NN0400286) has 1145 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 185 people using Groundwater sources.
How many people does White Post Mission NTUA serve? ▼
White Post Mission NTUA serves 185 people in Ft Defiance, Navajo Nation. It is a Native American-owned system using Groundwater water sources with 54 service connections.
What type of violations does White Post Mission NTUA have? ▼
White Post Mission NTUA has 1,145 total violations: 0 health-based violations (MCL exceedances or treatment failures), 1,044 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in White Post Mission NTUA water? ▼
No PFAS testing data is available for White Post Mission NTUA under the EPA's UCMR5 monitoring program.
What water source does White Post Mission NTUA use? ▼
White Post Mission 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.