Transient Non-Community Water System · PWS MT0002841
One Stop
Operator location Valier, Montana - smaller served population (≤ 999) at 500 people served; 237 SDWIS violations on record from groundwater sources.
- 500
- People served (this PWS)
- 237
- EPA violations (this PWS)
- 4
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
One Stop standing, high SDWIS violation third
500 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 2% is middle-third health share (≤ 23%). Population rank #29,264 of 29,740 among systems serving 500+.
The verdict
One Stop sits in the upper third of the sitemap cohort by violation count (237), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (500; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 2% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- #29,264 of 29,740
- Population · /systems
- #277 of 283
- Population · MT
- 237
- Total EPA violations on record
- 2%
- 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
- Transient Non-Community
- Owner Type
- Private
- Connections
- 2
- County
- Sanders
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 231
- Treatment Tech Violations
- 4
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 144 | 2015 |
| Revised Total Coliform Rule | MON | 34 | 2025 |
| Nitrate-Nitrite | MR | 21 | 2024 |
| E. COLI | MR | 19 | 2024 |
| Nitrate | MR | 13 | 1999 |
| Revised Total Coliform Rule | TT | 4 | 2018 |
Violation Count vs. the National Corpus
One Stop has 237 recorded EPA violations, 88% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 12% carry more. 2% of this system's own violations are health-based (4 of 237), and it ranks #29,264 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)
237 Higher than most more violations than 88% 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 One Stop
EPA SDWIS lists 500 people served and 2 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
237 violations · 500 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.
Cross-state systems with smaller service footprints
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with One Stop
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.