Community Water System · PWS NN3500268

Naschitti-Bisola NTUA

Ft Defiance, Navajo Nation 86504 - drinking water served from groundwater sources to 1,173 people, tracked in EPA SDWIS and UCMR5.

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

1,173
People served: 105
EPA violations: 0
Health-based: Untested
UCMR5 result

The verdict

EPA records 105 drinking-water violations at Naschitti-Bisola NTUA - below the Navajo Nation per-system average.

105
Total EPA violations on record: 0%
Health-based (MCL / treatment failure): 1,173
People served by this system: N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Naschitti-Bisola NTUA

Naschitti-Bisola NTUA is a native american-owned community water system that delivers drinking water to 1,173 residents in Ft Defiance, Navajo Nation through 343 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 105 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 96 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 3 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%).

Naschitti-Bisola NTUA's 105 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

1,173

Total Violations

105

Health-Based Violations

Water Source

Groundwater

System Details

System Type: Community
Owner Type: Native American
Connections: 343
School/Daycare: No
MCL Violations: 0
Monitoring Violations: 96
Treatment Tech Violations: 0

Violation History

Contaminant violations recorded by EPA.

Contaminant	Category	Count	Latest
Coliform (TCR)	MR	3	2012
Total Haloacetic Acids (HAA5)	MR	3	2020
TTHM	MR	3	2020
Stage 2 Disinfectants and Disinfection Byproducts Rule	MR	3	2013
cis-1,2-Dichloroethylene	MR	2	2008
Xylenes, Total	MR	2	2008
o-Dichlorobenzene	MR	2	2008
p-Dichlorobenzene	MR	2	2008
Vinyl chloride	MR	2	2008
1,1-Dichloroethylene	MR	2	2008
trans-1,2-Dichloroethylene	MR	2	2008
1,1,1-Trichloroethane	MR	2	2008
Carbon tetrachloride	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
Styrene	MR	2	2008
1,2,4-Trichlorobenzene	MR	2	2008
DICHLOROMETHANE	MR	2	2008
Trichloroethylene	MR	2	2008
1,2-Dichloroethane	MR	2	2008
Ethylbenzene	MR	2	2008
Revised Total Coliform Rule	Other	2	2016
1,2-Dichloropropane	MR	2	2008
Cadmium	MR	1	2008
Chromium	MR	1	2008
CYANIDE	MR	1	2008
Mercury	MR	1	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 Naschitti-Bisola 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 NN3500268 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	3	SDWIS / NN3500268 / 2456
2020	TTHM	MR	3	SDWIS / NN3500268 / 2950
2016	Revised Total Coliform Rule	Other	2	SDWIS / NN3500268 / 8000
2013	Stage 2 Disinfectants and Disinfection Byproducts Rule	MR	3	SDWIS / NN3500268 / 0600
2012	Coliform (TCR)	MR	3	SDWIS / NN3500268 / 3100
2008	cis-1,2-Dichloroethylene	MR	2	SDWIS / NN3500268 / 2380
2008	Xylenes, Total	MR	2	SDWIS / NN3500268 / 2955
2008	o-Dichlorobenzene	MR	2	SDWIS / NN3500268 / 2968
2008	p-Dichlorobenzene	MR	2	SDWIS / NN3500268 / 2969
2008	Vinyl chloride	MR	2	SDWIS / NN3500268 / 2976
2008	1,1-Dichloroethylene	MR	2	SDWIS / NN3500268 / 2977
2008	trans-1,2-Dichloroethylene	MR	2	SDWIS / NN3500268 / 2979
2008	1,1,1-Trichloroethane	MR	2	SDWIS / NN3500268 / 2981
2008	Carbon tetrachloride	MR	2	SDWIS / NN3500268 / 2982
2008	1,1,2-Trichloroethane	MR	2	SDWIS / NN3500268 / 2985

How Naschitti-Bisola NTUA Compares

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

Metric	Naschitti-Bisola NTUA	Navajo Nation avg	Federal benchmark
Total violations	105	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	1,173	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 Naschitti-Bisola NTUA water safe to drink? ▼

Naschitti-Bisola NTUA (PWS ID: NN3500268) has 105 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 1,173 people using Groundwater sources.

How many people does Naschitti-Bisola NTUA serve? ▼

Naschitti-Bisola NTUA serves 1,173 people in Ft Defiance, Navajo Nation. It is a Native American-owned system using Groundwater water sources with 343 service connections.

What type of violations does Naschitti-Bisola NTUA have? ▼

Naschitti-Bisola NTUA has 105 total violations: 0 health-based violations (MCL exceedances or treatment failures), 96 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.

Has PFAS been detected in Naschitti-Bisola NTUA water? ▼

No PFAS testing data is available for Naschitti-Bisola NTUA under the EPA's UCMR5 monitoring program.

What water source does Naschitti-Bisola NTUA use? ▼

Naschitti-Bisola 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.