Non-Transient Non-Community Water System · PWS MT0000953
East Decker Coal Mine
Operator location Decker, Montana - 0% of 31 violations are health-based (lower-third health share (≤ 1%)); groundwater source; 28 served per SDWIS.
- 28
- People served (this PWS)
- 31
- EPA violations (this PWS)
- 0
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
East Decker Coal Mine standing, mid SDWIS violation third
0% of 31 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%).
The verdict
East Decker Coal Mine lands in the middle third by violation volume (31), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is smaller (28; smaller served population (≤ 999)), so each violation row represents a compact service footprint. 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.
- 31
- Total EPA violations on record
- 0%
- Health-based (MCL / treatment failure)
- 28
- 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
- Non-Transient Non-Community
- Owner Type
- Private
- Connections
- 3
- County
- Big Horn
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 31
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Groundwater Rule | MR | 11 | 2025 |
| Lead and Copper Rule | MR | 5 | 2023 |
| TTHM | MR | 3 | 2004 |
| Revised Total Coliform Rule | MON | 3 | 2021 |
| Total Haloacetic Acids (HAA5) | MR | 3 | 2004 |
| OXAMYL | MR | 1 | 1996 |
| Nitrate | MR | 1 | 1981 |
| Carbofuran | MR | 1 | 1996 |
| Aldicarb sulfoxide | MR | 1 | 1996 |
| Aldicarb | MR | 1 | 1996 |
| Aldicarb sulfone | MR | 1 | 1996 |
Violation Count vs. the National Corpus
East Decker Coal Mine has 31 recorded EPA violations, 43% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 56% carry more. 0% of this system's own violations are health-based (0 of 31), 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)
31 Lower than most fewer violations than 56% 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 East Decker Coal Mine
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 MT0000953.
Sources: EPA SDWIS
Nationwide peers
31 violations · 28 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 East Decker Coal Mine
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Montana compares on the same EPA violation measures. Montana 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.