Community Water System · PWS NN0403005

Tsaile-Dine College NTUA

Ft Defiance, Navajo Nation 86504 - drinking water served from groundwater sources to 1,190 people, tracked in EPA SDWIS and UCMR5.

Compiled by PlainWater Editorial, Drinking Water Quality Editorial Team · May 15, 2026

1,190
People served: 124
EPA violations: 3
Health-based: Untested
UCMR5 result

The verdict

EPA records 124 drinking-water violations at Tsaile-Dine College NTUA, 2% of them health-based - below the Navajo Nation per-system average.

124
Total EPA violations on record: 2%
Health-based (MCL / treatment failure): 1,190
People served by this system: N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Tsaile-Dine College NTUA

Tsaile-Dine College NTUA is a native american-owned community water system that delivers drinking water to 1,190 residents in Ft Defiance, Navajo Nation through 348 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 124 total violations for this system , of which 3 (2%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 111 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 Coliform (TCR), recorded in 6 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%).

Tsaile-Dine College NTUA's 124 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

1,190

Total Violations

124

Health-Based Violations

Water Source

Groundwater

System Details

System Type: Community
Owner Type: Native American
Connections: 348
School/Daycare: No
MCL Violations: 3
Monitoring Violations: 111
Treatment Tech Violations: 0

Violation History

Contaminant violations recorded by EPA.

Contaminant	Category	Count	Latest
Coliform (TCR)	MR	6	2012
Total Haloacetic Acids (HAA5)	MR	6	2020
TTHM	MR	6	2020
Arsenic	MR	4	2018
Combined Radium (-226 and -228)	MR	3	2015
Arsenic	MCL	3	2014
1,2,4-Trichlorobenzene	MR	2	2008
cis-1,2-Dichloroethylene	MR	2	2008
DICHLOROMETHANE	MR	2	2008
p-Dichlorobenzene	MR	2	2008
1,1-Dichloroethylene	MR	2	2008
trans-1,2-Dichloroethylene	MR	2	2008
1,2-Dichloroethane	MR	2	2008
Carbon tetrachloride	MR	2	2008
1,2-Dichloropropane	MR	2	2008
Trichloroethylene	MR	2	2008
1,1,2-Trichloroethane	MR	2	2008
Tetrachloroethylene	MR	2	2008
CHLOROBENZENE	MR	2	2008
Benzene	MR	2	2008
Toluene	MR	2	2008
Ethylbenzene	MR	2	2008
Styrene	MR	2	2008
Public Notice	Other	2	2014
1,1,1-Trichloroethane	MR	2	2008
Stage 2 Disinfectants and Disinfection Byproducts Rule	MR	2	2013
o-Dichlorobenzene	MR	2	2008
Revised Total Coliform Rule	Other	2	2016
Xylenes, Total	MR	2	2008
Vinyl chloride	MR	2	2008

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 Tsaile-Dine College 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 NN0403005 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	6	SDWIS / NN0403005 / 2456
2020	TTHM	MR	6	SDWIS / NN0403005 / 2950
2018	Arsenic	MR	4	SDWIS / NN0403005 / 1005
2016	Revised Total Coliform Rule	Other	2	SDWIS / NN0403005 / 8000
2015	Combined Radium (-226 and -228)	MR	3	SDWIS / NN0403005 / 4010
2014	Arsenic	MCL	3	SDWIS / NN0403005 / 1005
2014	Public Notice	Other	2	SDWIS / NN0403005 / 7500
2013	Stage 2 Disinfectants and Disinfection Byproducts Rule	MR	2	SDWIS / NN0403005 / 0600
2012	Coliform (TCR)	MR	6	SDWIS / NN0403005 / 3100
2010	Nitrate	MR	1	SDWIS / NN0403005 / 1040
2010	Nitrite	MR	1	SDWIS / NN0403005 / 1041
2008	1,2,4-Trichlorobenzene	MR	2	SDWIS / NN0403005 / 2378
2008	cis-1,2-Dichloroethylene	MR	2	SDWIS / NN0403005 / 2380
2008	DICHLOROMETHANE	MR	2	SDWIS / NN0403005 / 2964
2008	p-Dichlorobenzene	MR	2	SDWIS / NN0403005 / 2969

How Tsaile-Dine College NTUA Compares

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

Metric	Tsaile-Dine College NTUA	Navajo Nation avg	Federal benchmark
Total violations	124	173.7	SDWA compliance, any non-zero count is a recorded breach
Health-based violations	3	8	Indicates a contaminant exceeded a federal MCL
PFAS detection	None	100%	EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served	1,190	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 Tsaile-Dine College NTUA water safe to drink? ▼

Tsaile-Dine College NTUA (PWS ID: NN0403005) has 124 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 1,190 people using Groundwater sources.

How many people does Tsaile-Dine College NTUA serve? ▼

Tsaile-Dine College NTUA serves 1,190 people in Ft Defiance, Navajo Nation. It is a Native American-owned system using Groundwater water sources with 348 service connections.

What type of violations does Tsaile-Dine College NTUA have? ▼

Tsaile-Dine College NTUA has 124 total violations: 3 health-based violations (MCL exceedances or treatment failures), 111 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.

Has PFAS been detected in Tsaile-Dine College NTUA water? ▼

No PFAS testing data is available for Tsaile-Dine College NTUA under the EPA's UCMR5 monitoring program.

What water source does Tsaile-Dine College NTUA use? ▼

Tsaile-Dine College 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.