Community Water System · PWS WY5680092
Ynp-Mammoth Hot Springs
Operator location Yellowstone National Park, Wyoming - lower-third violation load (≤ 21 violations) with 14 EPA violations; surface water source; 2,600 served (PWS-level, not municipal population).
- 2,600
- People served (this PWS)
- 14
- EPA violations (this PWS)
- 2
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Ynp-Mammoth Hot Springs standing, low SDWIS violation third
14 EPA SDWIS violations on record - lower-third violation load (≤ 21 violations). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 14% is middle-third health share (≤ 23%). Population rank #11,608 of 29,740 among systems serving 500+.
The verdict
Ynp-Mammoth Hot Springs is in the lower third by violation count (14; lower-third violation load (≤ 21 violations)). A low count does not mean the system is unmonitored - monitoring and reporting violations still appear in SDWIS. Population served is mid-pack at 2,600 (mid served population (≤ 3,309)). Health-based share is 14% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- #11,608 of 29,740
- Population · /systems
- #37 of 147
- Population · WY
- 14
- Total EPA violations on record
- 14%
- 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
- Federal
- Connections
- 274
- County
- Park
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 12
- Treatment Tech Violations
- 2
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| CARBON, TOTAL | MR | 3 | 2005 |
| Surface Water Treatment Rule | TT | 2 | 2005 |
| Coliform (TCR) | MR | 2 | 2013 |
| Surface Water Treatment Rule | MR | 2 | 2023 |
| Total Haloacetic Acids (HAA5) | MR | 1 | 2017 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 1980 |
| TTHM | MR | 1 | 2017 |
| Nitrate | MR | 1 | 1993 |
| Combined Radium (-226 and -228) | MR | 1 | 1980 |
Violation Count vs. the National Corpus
Ynp-Mammoth Hot Springs has 14 recorded EPA violations, 24% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 75% carry more. 14% of this system's own violations are health-based (2 of 14), and it ranks #11,608 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)
14 Among the lowest violation counts fewer violations than 75% 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
SDWIS compliance record for Ynp-Mammoth Hot Springs
14 violations on record for WY5680092; use EPA SDWIS to confirm return-to-compliance dates and monitoring categories.
Sources: EPA SDWIS
Nationwide peers
14 violations · 2,600 served: nearest cross-state SDWIS matches.
Cross-state systems with similarly light violation ledgers
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 Ynp-Mammoth Hot Springs
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Wyoming compares on the same EPA violation measures. Wyoming 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.