Community Water System · PWS MT0000418
Duncan Ranch Colony
Operator location Harlowton, Montana - smaller served population (≤ 999) at 96 people served; 252 SDWIS violations on record from groundwater sources.
- 96
- People served (this PWS)
- 252
- EPA violations (this PWS)
- 31
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Duncan Ranch Colony standing, high SDWIS violation third
96 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 12% is middle-third health share (≤ 23%).
The verdict
Duncan Ranch Colony sits in the upper third of the sitemap cohort by violation count (252), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (96; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 12% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 252
- Total EPA violations on record
- 12%
- Health-based (MCL / treatment failure)
- 96
- 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
- Private
- Connections
- 17
- County
- Wheatland
- School/Daycare
- No
- MCL Violations
- 31
- Monitoring Violations
- 211
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 43 | 2011 |
| Coliform (TCR) | MCL | 31 | 2014 |
| Lead and Copper Rule | MR | 12 | 2021 |
| E. COLI | MR | 12 | 2012 |
| Consumer Confidence Rule | Other | 6 | 2019 |
| Barium | MR | 4 | 1999 |
| Chromium | MR | 4 | 1999 |
| Mercury | MR | 4 | 1999 |
| Cadmium | MR | 4 | 1999 |
| Selenium | MR | 4 | 1999 |
| Fluoride | MR | 4 | 1999 |
| Arsenic | MR | 4 | 1999 |
| Endrin | MR | 3 | 1999 |
| BHC-GAMMA | MR | 3 | 1999 |
| Dalapon | MR | 3 | 1999 |
| Diquat | MR | 3 | 1999 |
| Endothall | MR | 3 | 1999 |
| OXAMYL | MR | 3 | 1999 |
| Simazine | MR | 3 | 1999 |
| Dinoseb | MR | 3 | 1999 |
| Hexachlorocyclopentadiene | MR | 3 | 1999 |
| Carbofuran | MR | 3 | 1999 |
| Aldicarb | MR | 3 | 1999 |
| LASSO | MR | 3 | 1999 |
| 2,3,7,8-TCDD | MR | 3 | 1999 |
| Heptachlor | MR | 3 | 1999 |
| Heptachlor epoxide | MR | 3 | 1999 |
| 2,4,5-TP | MR | 3 | 1999 |
| HEXACHLOROBENZENE | MR | 3 | 1999 |
| Pentachlorophenol | MR | 3 | 1999 |
Violation Count vs. the National Corpus
Duncan Ranch Colony has 252 recorded EPA violations, 88% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 12% carry more. 12% of this system's own violations are health-based (31 of 252), 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)
252 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 Duncan Ranch Colony
EPA SDWIS lists 96 people served and 17 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
252 violations · 96 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 Duncan Ranch Colony
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.