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Community Water System · PWS NN3500299

Tohatchi Public School

Tohatchi, Navajo Nation 87325 - drinking water served from groundwater sources to 240 people, tracked in EPA SDWIS and UCMR5.

240
People served
663
EPA violations
1
Health-based
Untested
UCMR5 result

The verdict

EPA records 663 drinking-water violations at Tohatchi Public School - above the Navajo Nation per-system average.

663
Total EPA violations on record
0%
Health-based (MCL / treatment failure)
240
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Tohatchi Public School

Tohatchi Public School is a local-owned community water system that delivers drinking water to 240 residents in Tohatchi, Navajo Nation through 60 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 663 total violations for this system , of which 1 (0%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 616 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 50 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%).

Tohatchi Public School's 663 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
240
Total Violations
663
Health-Based Violations
1
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
60
School/Daycare
Yes
MCL Violations
1
Monitoring Violations
616
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 50 2014
Nitrate MR 16 2021
Consumer Confidence Rule Other 11 2022
Nitrite MR 11 2021
Barium MR 9 2008
CYANIDE MR 9 2008
Mercury MR 9 2008
Diquat MR 9 2008
Endothall MR 9 2008
Glyphosate MR 9 2008
2,3,7,8-TCDD MR 9 2008
1,2-DIBROMO-3-CHLOROPROPANE MR 9 2008
ETHYLENE DIBROMIDE MR 9 2008
Arsenic MR 8 2011
Cadmium MR 8 2011
Chromium MR 8 2011
Selenium MR 8 2011
Antimony, Total MR 8 2011
Beryllium, Total MR 8 2011
Thallium, Total MR 8 2011
Endrin MR 8 2011
BHC-GAMMA MR 8 2011
Methoxychlor MR 8 2011
Dalapon MR 8 2011
Di(2-ethylhexyl) adipate MR 8 2011
OXAMYL MR 8 2011
Simazine MR 8 2011
Di(2-ethylhexyl) phthalate MR 8 2011
Picloram MR 8 2011
Dinoseb MR 8 2011

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 Tohatchi Public School.

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 NN3500299 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
2024 Revised Total Coliform Rule MON 8 SDWIS / NN3500299 / 8000
2024 Revised Total Coliform Rule RPT 3 SDWIS / NN3500299 / 8000
2024 Public Notice Other 2 SDWIS / NN3500299 / 7500
2022 Consumer Confidence Rule Other 11 SDWIS / NN3500299 / 7000
2021 Nitrate MR 16 SDWIS / NN3500299 / 1040
2021 Nitrite MR 11 SDWIS / NN3500299 / 1041
2019 Total Haloacetic Acids (HAA5) MR 5 SDWIS / NN3500299 / 2456
2019 TTHM MR 5 SDWIS / NN3500299 / 2950
2016 Revised Total Coliform Rule Other 4 SDWIS / NN3500299 / 8000
2014 Coliform (TCR) MR 50 SDWIS / NN3500299 / 3100
2013 Stage 2 Disinfectants and Disinfection Byproducts Rule MR 2 SDWIS / NN3500299 / 0600
2011 Arsenic MR 8 SDWIS / NN3500299 / 1005
2011 Cadmium MR 8 SDWIS / NN3500299 / 1015
2011 Chromium MR 8 SDWIS / NN3500299 / 1020
2011 Selenium MR 8 SDWIS / NN3500299 / 1045

How Tohatchi Public School Compares

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

Metric Tohatchi Public School Navajo Nation avg Federal benchmark
Total violations 663 173.7 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 1 8 Indicates a contaminant exceeded a federal MCL
PFAS detection None 100% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 240 984 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 Tohatchi Public School water safe to drink? ▼
Tohatchi Public School (PWS ID: NN3500299) has 663 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 240 people using Groundwater sources.
How many people does Tohatchi Public School serve? ▼
Tohatchi Public School serves 240 people in Tohatchi, Navajo Nation. It is a Local-owned system using Groundwater water sources with 60 service connections.
What type of violations does Tohatchi Public School have? ▼
Tohatchi Public School has 663 total violations: 1 health-based violations (MCL exceedances or treatment failures), 616 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Tohatchi Public School water? ▼
No PFAS testing data is available for Tohatchi Public School under the EPA's UCMR5 monitoring program.
What water source does Tohatchi Public School use? ▼
Tohatchi Public School 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.