Public water system · MT0000291
ActiveMiles City City of
At a glance
City of Miles City (PWSID MT0000291) is an active community water system in Custer County, Montana. It reports serving 9,565 people through 3,724 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in August 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
9,565
Service connections
3,724
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does City of Miles City compare with other water systems in Custer County?
By EPA's size categories, City of Miles City is a medium system (3,301 to 10,000 people). Custer County has 11 active public water systems, and City of Miles City is the largest of them by population served. Its population served is about 9.9 times the county average of 962 people per system, and accounts for 90% of the 10,579 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 Miles City is about 43% above 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. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 60 Montana systems (2.5%) list surface water as their primary source.
Who owns and regulates City of Miles City?
EPA lists City of Miles City 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. 4 of the 11 active systems in Custer County (36%) are also owned by a local government.
Does City of Miles City have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in August 2025. The violations listed here began between January 1997 and August 2025. By type: 7 monitoring and reporting, 3 required treatment not met, 1 public notice, recordkeeping or other and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Surface Water Treatment Rule (4 of them). EPA lists 9 as resolved and 3 as archived. 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. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-08-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Long Term 2 Enhanced Surface Water Treatment Rulecode 0800 | No | Archived |
| 2025-07-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Long Term 2 Enhanced Surface Water Treatment Rulecode 0800 | No | Archived |
| 2023-08-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
| 2022-12-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Surface Water Treatment Rulecode 0200 | No | Resolved |
| 2022-09-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2022-08-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2018-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2005-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-06-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1997-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chlorobenzenecode 2989 | No | Resolved |
| 1997-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,1-Trichloroethanecode 2981 | 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.
City of Miles City: frequently asked questions
Who runs City of Miles City?
City of Miles City (PWSID MT0000291) 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 Miles City serve?
City of Miles City reports serving 9,565 people through 3,724 service connections in Custer County, Montana.
Where does City of Miles City get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does City of Miles City have any drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in August 2025. 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 Miles City'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, 4 are health-based, and the most recent began in August 2025. 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 Miles City's water quality report?
As a community water system, City of Miles City 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 Custer County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Custer Co Water and Sewer Dist | Custer | 480 | Community | Purchased surface water |
| Pine Hills Youth Correct Facil | Custer | 193 | Community | Purchased surface water |
| Kinsey School District 63 | Custer | 86 | Non-transient non-community | Groundwater |
| Big Sky Camp and Rv Park | Custer | 56 | Transient non-community | Groundwater |
| Palisades Apartments | Custer | 50 | Community | Groundwater |
| Kircher School Dist 03 | Custer | 45 | Non-transient non-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, “Miles City City of, PWSID MT0000291, Montana”, https://aquacensus.com/water-systems/montana/miles-city-city-of-mt0000291 (data as of October 1, 2026).