Public water system · MT0000418
ActiveDuncan Ranch Colony
At a glance
Duncan Ranch Colony (PWSID MT0000418) is an active community water system in Wheatland County, Montana. It reports serving 96 people through 17 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in December 2021.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
96
Service connections
17
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Duncan Ranch Colony compare with other water systems in Wheatland County?
By EPA's size categories, Duncan Ranch Colony is a very small system (500 people or fewer). Wheatland County has 8 active public water systems, and Duncan Ranch Colony is the 6th-largest of them by population served. Its population served is well below the county average of 337 people per system, and accounts for 3.6% of the 2,697 people reported by systems filed under the county. Across Montana, the 2,378 active systems average 489 people each. Nationally, the average active community water system reports serving 6,703 people, so Duncan Ranch Colony is well below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Montana has 853 active community water systems, 36% of the state's 2,378 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,994 Montana systems (84%) list groundwater as their primary source.
Who owns and regulates Duncan Ranch Colony?
EPA lists Duncan Ranch Colony as privately owned. The MT state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 5 of the 8 active systems in Wheatland County (63%) are also privately owned.
Does Duncan Ranch Colony have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in December 2021. The violations listed here began between July 2011 and December 2021. By type: 7 monitoring and reporting, 3 contaminant level above the legal limit, 1 monitoring and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2021-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2021-06-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2015-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2014-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2013-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-11-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2012-09-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2012-09-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2011-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2011-07-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Duncan Ranch Colony: frequently asked questions
Who runs Duncan Ranch Colony?
Duncan Ranch Colony (PWSID MT0000418) is a community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Duncan Ranch Colony serve?
Duncan Ranch Colony reports serving 96 people through 17 service connections in Wheatland County, Montana.
Where does Duncan Ranch Colony get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Duncan Ranch Colony have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in December 2021. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Duncan Ranch Colony's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in December 2021. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find Duncan Ranch Colony's water quality report?
As a community water system, Duncan Ranch Colony must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Wheatland County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Cmrwa Musselshell Judith Rural Water Sys | Wheatland | 1,100 | Community | Groundwater |
| Harlowton City of | Wheatland | 1,050 | Community | Purchased groundwater |
| Martinsdale Colony | Wheatland | 150 | Community | Groundwater |
| Judith Gap Town of | Wheatland | 126 | Community | Groundwater |
| Springwater Colony | Wheatland | 100 | Community | Groundwater |
| Two Dot Water Users Company | Wheatland | 50 | Community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Duncan Ranch Colony, PWSID MT0000418, Montana”, https://aquacensus.com/water-systems/montana/duncan-ranch-colony-mt0000418 (data as of October 1, 2026).