Public water system · MT0004893
ActiveDayton Harbor Cottages
At a glance
Dayton Harbor Cottages (PWSID MT0004893) is an active transient non-community water system in Lake County, Montana. It reports serving 25 people through 8 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
25
Service connections
8
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Dayton Harbor Cottages compare with other water systems in Lake County?
By EPA's size categories, Dayton Harbor Cottages is a very small system (500 people or fewer). Lake County has 90 active public water systems. Its population served is well below the county average of 220 people per system, and accounts for 0.1% of the 19,829 people reported by systems filed under the county. Across Montana, the 2,378 active systems average 489 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Dayton Harbor Cottages is well below that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. Montana has 1,206 active transient non-community water systems, 51% 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 Dayton Harbor Cottages?
EPA lists Dayton Harbor Cottages as privately owned. 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. 71 of the 90 active systems in Lake County (79%) are also privately owned.
Does Dayton Harbor Cottages 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 2026. The violations listed here began between September 2015 and January 2026. By type: 4 monitoring, 4 required treatment not met and 4 monitoring and reporting. The contaminant or rule involved most often is Revised Total Coliform Rule (4 of them). EPA lists 11 as resolved and 1 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 |
|---|---|---|---|---|
| 2026-01-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2020-06-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-05-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2018-05-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Groundwater Rulecode 0700 | Yes | Resolved |
| 2017-05-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2015-12-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2015-12-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Groundwater Rulecode 0700 | Yes | Resolved |
| 2015-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2015-10-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Groundwater Rulecode 0700 | Yes | Resolved |
| 2015-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2015-09-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2015-09-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Groundwater Rulecode 0700 | 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.
Dayton Harbor Cottages: frequently asked questions
Who runs Dayton Harbor Cottages?
Dayton Harbor Cottages (PWSID MT0004893) is a transient non-community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Dayton Harbor Cottages serve?
Dayton Harbor Cottages reports serving 25 people through 8 service connections in Lake County, Montana.
Where does Dayton Harbor Cottages 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 Dayton Harbor Cottages 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 2026. 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 Dayton Harbor Cottages' 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 2026. For current results, consult EPA ECHO, or the MT state drinking water program.
Where can I find Dayton Harbor Cottages' water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Dayton Harbor Cottages is a transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
Other water systems in Lake County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Polson City of | Lake | 5,300 | Community | Groundwater |
| Ronan City of | Lake | 2,483 | Community | Surface water |
| Pablo Lake County Water and Sewer Dist | Lake | 2,175 | Community | Groundwater |
| St Ignatius Town of | Lake | 700 | Community | Groundwater |
| Woods Bay Water and Sewer District | Lake | 685 | Community | Groundwater |
| Wilson Foods | Lake | 600 | 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, “Dayton Harbor Cottages, PWSID MT0004893, Montana”, https://aquacensus.com/water-systems/montana/dayton-harbor-cottages-mt0004893 (data as of October 1, 2026).