Public water system · MT0000362
ActiveWilsall Water District
At a glance
Wilsall Water District (PWSID MT0000362) is an active community water system in Park County, Montana. It reports serving 250 people through 130 service connections. Its primary water source is groundwater under influence of 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 October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
250
Service connections
130
Primary source
GU
Groundwater under influence of surface water
System type
CWS
Community water system
System record
How does Wilsall Water District compare with other water systems in Park County?
By EPA's size categories, Wilsall Water District is a very small system (500 people or fewer). Park County has 59 active public water systems. Its population served is roughly in line with the county average of 271 people per system, and accounts for 1.6% of the 15,983 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 Wilsall Water District 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 under the influence of surface water is well or spring water that the regulator has found to be affected by nearby surface water, so it is regulated under the surface-water treatment rules. 8 Montana systems (0.3%) list groundwater under influence of surface water as their primary source.
Who owns and regulates Wilsall Water District?
EPA lists Wilsall Water District 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 59 active systems in Park County (8.5%) are also owned by a local government.
Does Wilsall Water District have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in October 2025. The violations listed here began between July 2010 and October 2025. By type: 6 monitoring and reporting, 3 required treatment not met, 2 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 (5 of them). EPA lists 11 as resolved and 1 as addressed. 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. Addressed means the violation is not resolved or archived and is covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-10-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2025-09-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Surface Water Treatment Rulecode 0200 | No | Resolved |
| 2025-09-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2025-08-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Surface Water Treatment Rulecode 0200 | No | Resolved |
| 2019-10-03 | Required treatment not metFailure to Filter (SWTR) · code 42 | Surface Water Treatment Rulecode 0200 | Yes | Addressed |
| 2018-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Single Sample · code 01 | Nitrate-Nitritecode 1038 | Yes | Resolved |
| 2013-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2013-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2011-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2011-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Asbestoscode 1094 | No | Resolved |
| 2010-10-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2010-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | 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.
Wilsall Water District: frequently asked questions
Who runs Wilsall Water District?
Wilsall Water District (PWSID MT0000362) is a community water system owned by a local government. It is regulated by the MT state drinking water program.
How many people does Wilsall Water District serve?
Wilsall Water District reports serving 250 people through 130 service connections in Park County, Montana.
Where does Wilsall Water District get its water?
EPA SDWIS lists this system's primary water source as groundwater under influence of surface water. Groundwater under the influence of surface water is well or spring water that the regulator has found to be affected by nearby surface water, so it is regulated under the surface-water treatment rules.
Does Wilsall Water District 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 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 Wilsall Water District'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 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 Wilsall Water District's water quality report?
As a community water system, Wilsall Water District 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 Park County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Livingston City of | Park | 7,500 | Community | Groundwater |
| Emigrant Rest Stop | Park | 800 | Transient non-community | Groundwater |
| Gardiner Park Co Water Dist | Park | 700 | Community | Groundwater |
| Sage Lodge | Park | 500 | Transient non-community | Groundwater |
| Yellowstone Travel Plaza Truck Stop | Park | 500 | Transient non-community | Groundwater |
| Chico Hot Springs | Park | 415 | Non-transient non-community | 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, “Wilsall Water District, PWSID MT0000362, Montana”, https://aquacensus.com/water-systems/montana/wilsall-water-district-mt0000362 (data as of October 1, 2026).