Community Water System · PWS MT0000187
Cooke City Water District
Operator location Cooke City, Montana - smaller served population (≤ 999) at 300 people served; 941 SDWIS violations on record from groundwater sources.
- 300
- People served (this PWS)
- 941
- EPA violations (this PWS)
- 43
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Cooke City Water District standing, high SDWIS violation third
300 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 5% is middle-third health share (≤ 23%).
The verdict
Cooke City Water District sits in the upper third of the sitemap cohort by violation count (941), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (300; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 5% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 941
- Total EPA violations on record
- 5%
- Health-based (MCL / treatment failure)
- 300
- 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
- Local
- Connections
- 98
- County
- Park
- School/Daycare
- No
- MCL Violations
- 35
- Monitoring Violations
- 875
- Treatment Tech Violations
- 8
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 35 | 2009 |
| DICHLOROMETHANE | MR | 27 | 2020 |
| 1,2-Dichloroethane | MR | 27 | 2020 |
| 1,1,1-Trichloroethane | MR | 27 | 2020 |
| 1,2-Dichloropropane | MR | 27 | 2020 |
| Tetrachloroethylene | MR | 27 | 2020 |
| Benzene | MR | 27 | 2020 |
| Toluene | MR | 27 | 2020 |
| Styrene | MR | 27 | 2020 |
| Xylenes, Total | MR | 27 | 2020 |
| o-Dichlorobenzene | MR | 27 | 2020 |
| p-Dichlorobenzene | MR | 27 | 2020 |
| 1,1-Dichloroethylene | MR | 27 | 2020 |
| Trichloroethylene | MR | 27 | 2020 |
| CHLOROBENZENE | MR | 27 | 2020 |
| Ethylbenzene | MR | 27 | 2020 |
| 1,2,4-Trichlorobenzene | MR | 27 | 2020 |
| cis-1,2-Dichloroethylene | MR | 27 | 2020 |
| Vinyl chloride | MR | 27 | 2020 |
| trans-1,2-Dichloroethylene | MR | 27 | 2020 |
| Carbon tetrachloride | MR | 27 | 2020 |
| 1,1,2-Trichloroethane | MR | 27 | 2020 |
| Revised Total Coliform Rule | MON | 25 | 2023 |
| Consumer Confidence Rule | Other | 20 | 2025 |
| Coliform (TCR) | MR | 19 | 2014 |
| Lead and Copper Rule | MR | 16 | 2014 |
| Di(2-ethylhexyl) phthalate | MR | 13 | 2021 |
| Nitrate-Nitrite | MR | 10 | 2020 |
| Thallium, Total | MR | 9 | 2005 |
| Nickel | MR | 9 | 2005 |
Violation Count vs. the National Corpus
Cooke City Water District has 941 recorded EPA violations, 99% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 1% carry more. 5% of this system's own violations are health-based (43 of 941), 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)
941 Higher than most more violations than 99% 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 Cooke City Water District
EPA SDWIS lists 300 people served and 98 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
941 violations · 300 served: nearest cross-state SDWIS matches.
Cross-state systems with comparable violation load
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
What to do with Cooke City Water District
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.