PlainWater
States → Navajo Nation

Non-Transient Non-Community Water System · PWS NN0400821

Twin Arrows Navajo Casino Internal

Church Rock, Navajo Nation 87311 - drinking water served from groundwater sources to 25 people, tracked in EPA SDWIS and UCMR5.

25
People served
93
EPA violations
0
Health-based
Untested
UCMR5 result

The verdict

EPA records 93 drinking-water violations at Twin Arrows Navajo Casino Internal - below the Navajo Nation per-system average.

93
Total EPA violations on record
0%
Health-based (MCL / treatment failure)
25
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Twin Arrows Navajo Casino Internal

Twin Arrows Navajo Casino Internal is a native american-owned non-transient non-community water system that delivers drinking water to 25 residents in Church Rock, Navajo Nation through 1 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 93 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 80 monitoring and reporting violations are on file. The most recent violation on record dates to 2023.

The most frequently cited contaminant at this system is Revised Total Coliform Rule, recorded in 21 violations (MON). 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%).

Twin Arrows Navajo Casino Internal's 93 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
25
Total Violations
93
Health-Based Violations
0
Water Source
Groundwater

System Details

System Type
Non-Transient Non-Community
Owner Type
Native American
Connections
1
School/Daycare
No
MCL Violations
0
Monitoring Violations
80
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Revised Total Coliform Rule MON 21 2021
Total Haloacetic Acids (HAA5) MR 18 2021
TTHM MR 18 2021
Coliform (TCR) MR 14 2015
Revised Total Coliform Rule RPT 10 2023
Lead and Copper Rule MR 6 2015
Chlorine MR 3 2021

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 Twin Arrows Navajo Casino Internal.

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 NN0400821 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
2023 Revised Total Coliform Rule RPT 10 SDWIS / NN0400821 / 8000
2021 Revised Total Coliform Rule MON 21 SDWIS / NN0400821 / 8000
2021 Total Haloacetic Acids (HAA5) MR 18 SDWIS / NN0400821 / 2456
2021 TTHM MR 18 SDWIS / NN0400821 / 2950
2021 Chlorine MR 3 SDWIS / NN0400821 / 0999
2015 Coliform (TCR) MR 14 SDWIS / NN0400821 / 3100
2015 Lead and Copper Rule MR 6 SDWIS / NN0400821 / 5000

How Twin Arrows Navajo Casino Internal Compares

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

Metric Twin Arrows Navajo Casino Internal Navajo Nation avg Federal benchmark
Total violations 93 173.7 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 25 984 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 Twin Arrows Navajo Casino Internal water safe to drink? ▼
Twin Arrows Navajo Casino Internal (PWS ID: NN0400821) has 93 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 25 people using Groundwater sources.
How many people does Twin Arrows Navajo Casino Internal serve? ▼
Twin Arrows Navajo Casino Internal serves 25 people in Church Rock, Navajo Nation. It is a Native American-owned system using Groundwater water sources with 1 service connections.
What type of violations does Twin Arrows Navajo Casino Internal have? ▼
Twin Arrows Navajo Casino Internal has 93 total violations: 0 health-based violations (MCL exceedances or treatment failures), 80 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Twin Arrows Navajo Casino Internal water? ▼
No PFAS testing data is available for Twin Arrows Navajo Casino Internal under the EPA's UCMR5 monitoring program.
What water source does Twin Arrows Navajo Casino Internal use? ▼
Twin Arrows Navajo Casino Internal uses Groundwater as its primary water source. It is classified as a Non-Transient Non-Community Water System, serving the same people for at least 6 months per year.
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.