Community Water System · PWS NN0403023
Round Rock NTUA
Operator location Ft Defiance, Navajo Nation - 43% of 61 violations are health-based (upper-third health share (> 23%)); groundwater source; 876 served per SDWIS.
- 876
- People served (this PWS)
- 61
- EPA violations (this PWS)
- 26
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Round Rock NTUA standing, mid SDWIS violation third
43% of 61 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 43% is upper-third health share (> 23%). Population rank #21,454 of 29,740 among systems serving 500+.
The verdict
Round Rock NTUA lands in the middle third by violation volume (61), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is smaller (876; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 43% - most of this ledger is MCL or treatment-technique exceedance. No UCMR5 PFAS test appears for this system in this extract.
- #21,454 of 29,740
- Population · /systems
- #53 of 82
- Population · NN
- 61
- Total EPA violations on record
- 43%
- Health-based (MCL / treatment failure)
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
- 256
- School/Daycare
- No
- MCL Violations
- 26
- Monitoring Violations
- 23
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Combined Radium (-226 and -228) | MCL | 24 | 2013 |
| Coliform (TCR) | MR | 9 | 2012 |
| Nitrate | MR | 3 | 2010 |
| TTHM | MR | 3 | 2020 |
| Stage 2 Disinfectants and Disinfection Byproducts Rule | MR | 3 | 2013 |
| Total Haloacetic Acids (HAA5) | MR | 3 | 2020 |
| Revised Total Coliform Rule | Other | 2 | 2016 |
| Coliform (TCR) | MCL | 2 | 2007 |
| Nitrite | MR | 1 | 2010 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 2004 |
Violation Count vs. the National Corpus
Round Rock NTUA has 61 recorded EPA violations, 62% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 38% carry more. 43% of this system's own violations are health-based (26 of 61), and it ranks #21,454 of 29,740 by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
61 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
Health-based violations on Round Rock NTUA
26 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for NN0403023.
Sources: EPA SDWIS
Nationwide peers
61 violations · 876 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.
Cross-state systems with smaller service footprints
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Round Rock 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.