Community Water System · PWS 093500302
Rock Springs Community - NTUA
Operator location Fort Defiance, EPA Region 9 — Tribal Water Systems - 0% of 67 violations are health-based (lower-third health share (≤ 1%)); groundwater source; 1,574 served per SDWIS.
- 1,574
- People served (this PWS)
- 67
- EPA violations (this PWS)
- 0
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Rock Springs Community - NTUA standing, mid SDWIS violation third
0% of 67 recorded violations are health-based - lower-third health share (≤ 1%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 0% is lower-third health share (≤ 1%). Population rank #15,514 of 29,740 among systems serving 500+.
The verdict
Rock Springs Community - NTUA lands in the middle third by violation volume (67), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is mid-pack at 1,574 (mid served population (≤ 3,309)). Health-based share is only 0% - almost all of this trail is monitoring or reporting. No UCMR5 PFAS test appears for this system in this extract.
- #15,514 of 29,740
- Population · /systems
- #71 of 129
- Population · 09
- 67
- Total EPA violations on record
- 0%
- 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
- 410
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 38
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Toluene | MR | 9 | 2016 |
| Di(2-ethylhexyl) phthalate | MR | 5 | 2016 |
| Coliform (TCR) | MR | 3 | 2015 |
| Barium | MR | 2 | 2011 |
| Thallium, Total | MR | 2 | 2011 |
| Cadmium | MR | 1 | 2011 |
| Chromium | MR | 1 | 2011 |
| CYANIDE | MR | 1 | 2011 |
| Mercury | MR | 1 | 2011 |
| Selenium | MR | 1 | 2011 |
| Antimony, Total | MR | 1 | 2011 |
| Beryllium, Total | MR | 1 | 2011 |
| Xylenes, Total | MR | 1 | 2001 |
| Total Polychlorinated Biphenyls (PCB) | MR | 1 | 2001 |
| DICHLOROMETHANE | MR | 1 | 2001 |
| Combined Radium (-226 and -228) | MR | 1 | 2008 |
| Total Haloacetic Acids (HAA5) | MR | 1 | 2014 |
| TTHM | MR | 1 | 2014 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 2008 |
| Arsenic | MR | 1 | 2011 |
| Nitrate | MR | 1 | 2011 |
| Consumer Confidence Rule | Other | 1 | 2002 |
| Fluoride | MR | 1 | 2011 |
Violation Count vs. the National Corpus
Rock Springs Community - NTUA has 67 recorded EPA violations, 64% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 36% carry more. 0% of this system's own violations are health-based (0 of 67), and it ranks #15,514 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)
67 Around the middle fewer violations than 36% 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 Rock Springs Community - NTUA
0 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for 093500302.
Sources: EPA SDWIS
Nationwide peers
67 violations · 1,574 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 near this population served
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Rock Springs Community - NTUA
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in EPA Region 9 — Tribal Water Systems compares on the same EPA violation measures. EPA Region 9 — Tribal Water Systems 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.