Public water system · MT0000174
ActiveChinook City of
At a glance
City of Chinook (PWSID MT0000174) is an active community water system in Blaine County, Montana. It reports serving 1,300 people through 807 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, 8 are health-based, and the most recent began in October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,300
Service connections
807
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does City of Chinook compare with other water systems in Blaine County?
By EPA's size categories, City of Chinook is a small system (501 to 3,300 people). Blaine County has 12 active public water systems, and City of Chinook is the largest of them by population served. Its population served is about 5.8 times the county average of 223 people per system, and accounts for 49% of the 2,672 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 Chinook 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. 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 Chinook?
EPA lists City of Chinook 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 12 active systems in Blaine County (33%) are also owned by a local government.
Does City of Chinook have drinking water violations?
Of the 12 most recent violations in EPA's records, 8 are health-based, and the most recent began in October 2025. The violations listed here began between November 1997 and October 2025. By type: 6 contaminant level above the legal limit, 4 monitoring and reporting and 2 required treatment not met. The contaminant or rule involved most often is Haloacetic acids (HAA5) (5 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 |
|---|---|---|---|---|
| 2025-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2025-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2025-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2025-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2014-10-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2011-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2004-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Resolved |
| 2003-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Resolved |
| 2000-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Dichloromethanecode 2964 | Yes | Resolved |
| 1999-01-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1997-11-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | 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 Chinook: frequently asked questions
Who runs City of Chinook?
City of Chinook (PWSID MT0000174) 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 Chinook serve?
City of Chinook reports serving 1,300 people through 807 service connections in Blaine County, Montana.
Where does City of Chinook 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 Chinook have any drinking water violations?
Of the 12 most recent violations in EPA's records, 8 are health-based, and the most recent began in October 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 Chinook'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, 8 are health-based, and the most recent began in October 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 Chinook's water quality report?
As a community water system, City of Chinook 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 Blaine County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Harlem City of | Blaine | 820 | Community | Surface water |
| Perrys Water Service | Blaine | 100 | Community | Purchased surface water |
| Turner School District No 43 | Blaine | 97 | Non-transient non-community | Groundwater |
| Hartland Colony | Blaine | 73 | Community | Groundwater |
| The Border Bar | Blaine | 52 | Transient non-community | Groundwater |
| Turner Colony | Blaine | 50 | Community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Chinook City of, PWSID MT0000174, Montana”, https://aquacensus.com/water-systems/montana/chinook-city-of-mt0000174 (data as of October 1, 2026).