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Community Water System · PWS NN0403009

Gap-Cedar Ridge NTUA

Fort Defiance, Navajo Nation 86504-0170 - drinking water served from groundwater sources to 1,125 people, tracked in EPA SDWIS and UCMR5.

1,125
People served
88
EPA violations
0
Health-based
Untested
UCMR5 result

The verdict

EPA records 88 drinking-water violations at Gap-Cedar Ridge NTUA - below the Navajo Nation per-system average.

88
Total EPA violations on record
0%
Health-based (MCL / treatment failure)
1,125
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Gap-Cedar Ridge NTUA

Gap-Cedar Ridge NTUA is a native american-owned community water system that delivers drinking water to 1,125 residents in Fort Defiance, Navajo Nation through 329 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 88 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 86 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 4 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%).

Gap-Cedar Ridge NTUA's 88 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
1,125
Total Violations
88
Health-Based Violations
0
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Native American
Connections
329
School/Daycare
No
MCL Violations
0
Monitoring Violations
86
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 4 2011
1,2-DIBROMO-3-CHLOROPROPANE MR 3 2014
ETHYLENE DIBROMIDE MR 3 2014
Nitrate MR 2 2015
Endrin MR 2 2014
BHC-GAMMA MR 2 2014
Methoxychlor MR 2 2014
Toxaphene MR 2 2014
Diquat MR 2 2014
Endothall MR 2 2014
Glyphosate MR 2 2014
Simazine MR 2 2014
Di(2-ethylhexyl) phthalate MR 2 2014
Atrazine MR 2 2014
LASSO MR 2 2014
2,3,7,8-TCDD MR 2 2014
Heptachlor MR 2 2014
Heptachlor epoxide MR 2 2014
Benzo(a)pyrene MR 2 2014
Total Polychlorinated Biphenyls (PCB) MR 2 2014
Chlordane MR 2 2014
TTHM MR 2 2020
HEXACHLOROBENZENE MR 2 2014
Hexachlorocyclopentadiene MR 2 2014
Di(2-ethylhexyl) adipate MR 2 2014
Total Haloacetic Acids (HAA5) MR 2 2020
CYANIDE MR 1 2001
Dalapon MR 1 2014
OXAMYL MR 1 2014
Picloram MR 1 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 Gap-Cedar Ridge 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 NN0403009 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 TTHM MR 2 SDWIS / NN0403009 / 2950
2020 Total Haloacetic Acids (HAA5) MR 2 SDWIS / NN0403009 / 2456
2015 Nitrate MR 2 SDWIS / NN0403009 / 1040
2014 1,2-DIBROMO-3-CHLOROPROPANE MR 3 SDWIS / NN0403009 / 2931
2014 ETHYLENE DIBROMIDE MR 3 SDWIS / NN0403009 / 2946
2014 Endrin MR 2 SDWIS / NN0403009 / 2005
2014 BHC-GAMMA MR 2 SDWIS / NN0403009 / 2010
2014 Methoxychlor MR 2 SDWIS / NN0403009 / 2015
2014 Toxaphene MR 2 SDWIS / NN0403009 / 2020
2014 Diquat MR 2 SDWIS / NN0403009 / 2032
2014 Endothall MR 2 SDWIS / NN0403009 / 2033
2014 Glyphosate MR 2 SDWIS / NN0403009 / 2034
2014 Simazine MR 2 SDWIS / NN0403009 / 2037
2014 Di(2-ethylhexyl) phthalate MR 2 SDWIS / NN0403009 / 2039
2014 Atrazine MR 2 SDWIS / NN0403009 / 2050

How Gap-Cedar Ridge NTUA Compares

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

Metric Gap-Cedar Ridge NTUA Navajo Nation avg Federal benchmark
Total violations 88 173.7 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 1,125 984 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 Gap-Cedar Ridge NTUA water safe to drink? ▼
Gap-Cedar Ridge NTUA (PWS ID: NN0403009) has 88 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 1,125 people using Groundwater sources.
How many people does Gap-Cedar Ridge NTUA serve? ▼
Gap-Cedar Ridge NTUA serves 1,125 people in Fort Defiance, Navajo Nation. It is a Native American-owned system using Groundwater water sources with 329 service connections.
What type of violations does Gap-Cedar Ridge NTUA have? ▼
Gap-Cedar Ridge NTUA has 88 total violations: 0 health-based violations (MCL exceedances or treatment failures), 86 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Gap-Cedar Ridge NTUA water? ▼
No PFAS testing data is available for Gap-Cedar Ridge NTUA under the EPA's UCMR5 monitoring program.
What water source does Gap-Cedar Ridge NTUA use? ▼
Gap-Cedar Ridge 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.