Public water system · MT0001922
ActiveHilltop Terrace Subdivision
At a glance
Hilltop Terrace Subdivision (PWSID MT0001922) is an active community water system in Flathead County, Montana. It reports serving 230 people through 89 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, one is health-based, and the most recent began in October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
230
Service connections
89
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Hilltop Terrace Subdivision compare with other water systems in Flathead County?
By EPA's size categories, Hilltop Terrace Subdivision is a very small system (500 people or fewer). Flathead County has 327 active public water systems. Its population served is about 29% below the county average of 324 people per system, and accounts for 0.2% of the 105,781 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 Hilltop Terrace Subdivision 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 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 Hilltop Terrace Subdivision?
EPA lists Hilltop Terrace Subdivision 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. 263 of the 327 active systems in Flathead County (80%) are also privately owned.
Does Hilltop Terrace Subdivision have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in October 2025. The violations listed here began between January 2017 and October 2025. By type: 6 public notice, recordkeeping or other, 3 monitoring and reporting, 2 monitoring and 1 required treatment not met. The contaminant or rule involved most often is Consumer Confidence Rule (6 of them). EPA lists 11 as resolved and 1 as unaddressed. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2022-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2021-10-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2021-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2020-10-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2020-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2020-06-02 | Required treatment not metTreatment Technique, Level 1 Assessment (RTCR) · code 2A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2020-06-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Resolved |
| 2017-05-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | 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.
Hilltop Terrace Subdivision: frequently asked questions
Who runs Hilltop Terrace Subdivision?
Hilltop Terrace Subdivision (PWSID MT0001922) is a community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Hilltop Terrace Subdivision serve?
Hilltop Terrace Subdivision reports serving 230 people through 89 service connections in Flathead County, Montana.
Where does Hilltop Terrace Subdivision 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 Hilltop Terrace Subdivision have any drinking water violations?
Of the 12 most recent violations in EPA's records, one is 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 Hilltop Terrace Subdivision'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, one is 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 Hilltop Terrace Subdivision's water quality report?
As a community water system, Hilltop Terrace Subdivision 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 Flathead County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Kalispell Public Works | Flathead | 25,000 | Community | Groundwater |
| Whitefish City of | Flathead | 10,418 | Community | Surface water |
| Flathead County Water and Sewer | Flathead | 7,775 | Community | Groundwater |
| Bigfork County Water and Sewer | Flathead | 6,100 | Community | Groundwater |
| Columbia Falls City of | Flathead | 4,450 | Community | Groundwater |
| Ridge Run | Flathead | 3,500 | 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, “Hilltop Terrace Subdivision, PWSID MT0001922, Montana”, https://aquacensus.com/water-systems/montana/hilltop-terrace-subdivision-mt0001922 (data as of October 1, 2026).