Community Water System · PWS MT0000174
Chinook City Of
Operator location Chinook, Montana - 57% of 49 violations are health-based (upper-third health share (> 23%)); surface water source; 1,300 served per SDWIS.
- 1,300
- People served (this PWS)
- 49
- EPA violations (this PWS)
- 28
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Chinook City Of standing, mid SDWIS violation third
57% of 49 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 57% is upper-third health share (> 23%). Population rank #17,157 of 29,740 among systems serving 500+.
The verdict
Chinook City Of lands in the middle third by violation volume (49), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is mid-pack at 1,300 (mid served population (≤ 3,309)). Health-based share is 57% - most of this ledger is MCL or treatment-technique exceedance. No UCMR5 PFAS test appears for this system in this extract.
- #17,157 of 29,740
- Population · /systems
- #109 of 283
- Population · MT
- 49
- Total EPA violations on record
- 57%
- 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
- Local
- Connections
- 807
- County
- Blaine
- School/Daycare
- No
- MCL Violations
- 14
- Monitoring Violations
- 20
- Treatment Tech Violations
- 14
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Surface Water Treatment Rule | TT | 14 | 1999 |
| Total Haloacetic Acids (HAA5) | MCL | 13 | 2025 |
| Fluoride | MR | 6 | 2004 |
| Coliform (TCR) | MR | 6 | 2014 |
| Arsenic | MR | 3 | 2002 |
| Thallium, Total | MR | 1 | 1994 |
| Nickel | MR | 1 | 1994 |
| Antimony, Total | MR | 1 | 1994 |
| Nitrate | MR | 1 | 1993 |
| o-Dichlorobenzene | MR | 1 | 1993 |
| DICHLOROMETHANE | MCL | 1 | 2000 |
Violation Count vs. the National Corpus
Chinook City Of has 49 recorded EPA violations, 56% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 44% carry more. 57% of this system's own violations are health-based (28 of 49), and it ranks #17,157 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)
49 Around the middle fewer violations than 44% 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 Chinook City Of
28 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for MT0000174.
Sources: EPA SDWIS
Nationwide peers
49 violations · 1,300 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 Chinook City Of
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.