Public water system · MT0000201
ActiveDillon City of
At a glance
City of Dillon (PWSID MT0000201) is an active community water system in Beaverhead County, Montana. It reports serving 4,300 people through 1,920 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 7 violations for this system; none is health-based, and the most recent began in May 2012.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
4,300
Service connections
1,920
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Dillon compare with other water systems in Beaverhead County?
By EPA's size categories, City of Dillon is a medium system (3,301 to 10,000 people). Beaverhead County has 48 active public water systems, and City of Dillon is the largest of them by population served. Its population served is about 22 times the county average of 198 people per system, and accounts for 45% of the 9,494 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 City of Dillon is about 36% 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 City of Dillon?
EPA lists City of Dillon as owned by a local government. 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. 3 of the 48 active systems in Beaverhead County (6.3%) are also owned by a local government.
Does City of Dillon have drinking water violations?
EPA's records list 7 violations for this system; none is health-based, and the most recent began in May 2012. The violations listed here began between January 1993 and May 2012. By type: 7 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (5 of them). EPA lists 7 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 |
|---|---|---|---|---|
| 2012-05-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2011-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2005-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2002-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1995-12-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1995-11-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1993-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
All 7 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.
City of Dillon: frequently asked questions
Who runs City of Dillon?
City of Dillon (PWSID MT0000201) is a community water system owned by a local government. It is regulated by the MT state drinking water program.
How many people does City of Dillon serve?
City of Dillon reports serving 4,300 people through 1,920 service connections in Beaverhead County, Montana.
Where does City of Dillon 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 City of Dillon have any drinking water violations?
EPA's records list 7 violations for this system; none is health-based, and the most recent began in May 2012. 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 City of Dillon'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. EPA's records list 7 violations for this system; none is health-based, and the most recent began in May 2012. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find City of Dillon's water quality report?
As a community water system, City of Dillon 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 Beaverhead County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Town Pump Dillon 2 | Beaverhead | 924 | Transient non-community | Groundwater |
| Bannack St Park Visitor Center | Beaverhead | 410 | Transient non-community | Groundwater |
| Maverick Mountain Resort LLC | Beaverhead | 340 | Transient non-community | Groundwater under influence of surface water |
| Keller Subdivision No 2 Hoa | Beaverhead | 300 | Community | Groundwater |
| Hildreth Subdivision No 2 | Beaverhead | 300 | Community | Groundwater |
| Lima Town of | Beaverhead | 279 | 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, “Dillon City of, PWSID MT0000201, Montana”, https://aquacensus.com/water-systems/montana/dillon-city-of-mt0000201 (data as of October 1, 2026).