Public water system · MT0000355
ActiveWestby Town of
At a glance
Town of Westby (PWSID MT0000355) is an active community water system in Sheridan County, Montana. It reports serving 172 people through 106 service connections. Its primary water source is purchased 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 January 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
172
Service connections
106
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Town of Westby compare with other water systems in Sheridan County?
By EPA's size categories, Town of Westby is a very small system (500 people or fewer). Sheridan County has 8 active public water systems, and Town of Westby is the 3rd-largest of them by population served. Its population served is about half of the county average of 346 people per system, and accounts for 6.2% of the 2,764 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 Town of Westby 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. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 212 Montana systems (8.9%) list purchased surface water as their primary source.
Who owns and regulates Town of Westby?
EPA lists Town of Westby 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. 5 of the 8 active systems in Sheridan County (63%) are also owned by a local government.
Does Town of Westby have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in January 2022. The violations listed here began between April 2013 and January 2022. By type: 8 monitoring and reporting and 4 contaminant level above the legal limit. The contaminant or rule involved most often is Arsenic (7 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 |
|---|---|---|---|---|
| 2022-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2022-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2019-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Resolved |
| 2018-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Resolved |
| 2015-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2015-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2014-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2014-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2014-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2014-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Resolved |
| 2013-11-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2013-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | 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.
Town of Westby: frequently asked questions
Who runs Town of Westby?
Town of Westby (PWSID MT0000355) is a community water system owned by a local government. It is regulated by the MT state drinking water program.
How many people does Town of Westby serve?
Town of Westby reports serving 172 people through 106 service connections in Sheridan County, Montana.
Where does Town of Westby get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Town of Westby 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 January 2022. 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 Town of Westby'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 January 2022. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find Town of Westby's water quality report?
As a community water system, Town of Westby 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 Sheridan County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Plentywood Water Department | Sheridan | 1,700 | Community | Purchased surface water |
| Medicine Lake Town of | Sheridan | 600 | Community | Purchased surface water |
| Outlook County Sewer and Water | Sheridan | 96 | Community | Groundwater |
| Antelope County Water and Sewer | Sheridan | 59 | Community | Purchased surface water |
| Brush Lake State Park | Sheridan | 58 | Transient non-community | Purchased surface water |
| Sunset Camping LLC | Sheridan | 42 | Transient non-community | Purchased surface water |
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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, “Westby Town of, PWSID MT0000355, Montana”, https://aquacensus.com/water-systems/montana/westby-town-of-mt0000355 (data as of October 1, 2026).