Community Water System · PWS NN3500239
Whitehorse Lake NTUA
Operator location Ft Defiance, Navajo Nation - smaller served population (≤ 999) at 277 people served; 60 SDWIS violations on record from surface water sources.
- 277
- People served (this PWS)
- 60
- EPA violations (this PWS)
- 4
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Whitehorse Lake NTUA standing, mid SDWIS violation third
277 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 7% is middle-third health share (≤ 23%).
The verdict
Whitehorse Lake NTUA lands in the middle third by violation volume (60), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is smaller (277; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 7% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 60
- Total EPA violations on record
- 7%
- Health-based (MCL / treatment failure)
- 277
- People served by this PWS (SDWIS)
- N/A
- PFAS compounds detected (UCMR5)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Community
- Owner Type
- Native American
- Connections
- 81
- School/Daycare
- No
- MCL Violations
- 4
- Monitoring Violations
- 45
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Nitrite | MR | 4 | 2013 |
| Antimony, Total | MCL | 4 | 2010 |
| Mercury | MR | 3 | 2008 |
| Thallium, Total | MR | 3 | 2008 |
| Endothall | MR | 3 | 2014 |
| Glyphosate | MR | 3 | 2014 |
| Total Polychlorinated Biphenyls (PCB) | MR | 3 | 2008 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 3 | 2008 |
| Nitrate | MR | 3 | 2013 |
| Coliform (TCR) | MR | 3 | 2012 |
| 2,3,7,8-TCDD | MR | 3 | 2014 |
| Fluoride | MR | 3 | 2008 |
| ETHYLENE DIBROMIDE | MR | 3 | 2008 |
| Diquat | MR | 3 | 2014 |
| Stage 2 Disinfectants and Disinfection Byproducts Rule | MR | 2 | 2013 |
| Combined Uranium | MR | 1 | 2005 |
| Combined Radium (-226 and -228) | MR | 1 | 2005 |
| Revised Total Coliform Rule | Other | 1 | 2016 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 2005 |
Violation Count vs. the National Corpus
Whitehorse Lake NTUA has 60 recorded EPA violations, 61% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 38% carry more. 7% of this system's own violations are health-based (4 of 60), and it ranks unranked by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
60 Around the middle fewer violations than 38% of 29,740 water systems
the national water-system corpus, bucketed by value
Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS · 2026-05-15
Population served record for Whitehorse Lake NTUA
EPA SDWIS lists 277 people served and 81 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
60 violations · 277 served: nearest cross-state SDWIS matches.
Cross-state systems near this violation count
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
What to do with Whitehorse Lake NTUA
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Navajo Nation compares on the same EPA violation measures. Navajo Nation systems
- Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
- Find and compare another public water system by name or PWSID. Search systems
EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.