Public water system · MT0002743
ActiveRosemarys Addition
At a glance
Rosemarys Addition (PWSID MT0002743) is an active community water system in Lewis and Clark County, Montana. It reports serving 30 people through 14 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, none is health-based, and the most recent began in October 2014.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
30
Service connections
14
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Rosemarys Addition compare with other water systems in Lewis and Clark County?
By EPA's size categories, Rosemarys Addition is a very small system (500 people or fewer). Lewis and Clark County has 165 active public water systems. Its population served is well below the county average of 413 people per system, and accounts for less than 0.1% of the 68,071 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 Rosemarys Addition 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 Rosemarys Addition?
EPA lists Rosemarys Addition 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. 134 of the 165 active systems in Lewis and Clark County (81%) are also privately owned.
Does Rosemarys Addition have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2014. The violations listed here began between January 2002 and October 2014. By type: 11 monitoring and reporting and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Lead and Copper Rule (2 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 |
|---|---|---|---|---|
| 2014-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2012-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Resolved |
| 2007-02-05 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2004-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Ethylbenzenecode 2992 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Picloramcode 2040 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chlorobenzenecode 2989 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | o-Dichlorobenzenecode 2968 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 2,4,5-TP (Silvex)code 2110 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Pentachlorophenolcode 2326 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Xylenes, Totalcode 2955 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Dinosebcode 2041 | 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.
Rosemarys Addition: frequently asked questions
Who runs Rosemarys Addition?
Rosemarys Addition (PWSID MT0002743) is a community water system privately owned. It is regulated by the MT state drinking water program.
How many people does Rosemarys Addition serve?
Rosemarys Addition reports serving 30 people through 14 service connections in Lewis and Clark County, Montana.
Where does Rosemarys Addition 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 Rosemarys Addition have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2014. 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 Rosemarys Addition'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, none is health-based, and the most recent began in October 2014. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.
Where can I find Rosemarys Addition's water quality report?
As a community water system, Rosemarys Addition 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 Lewis and Clark County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Helena Water System | Lewis and Clark | 32,091 | Community | Surface water |
| East Helena City of | Lewis and Clark | 2,114 | Community | Groundwater |
| Eastgate Village Sewer and Water | Lewis and Clark | 2,000 | Community | Groundwater |
| Va Medical Center Helena | Lewis and Clark | 1,275 | Community | Purchased surface water |
| Helena Leisure LLC | Lewis and Clark | 1,200 | Community | Groundwater |
| Bobs Valley Service Inc. | Lewis and Clark | 1,032 | Non-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, “Rosemarys Addition, PWSID MT0002743, Montana”, https://aquacensus.com/water-systems/montana/rosemarys-addition-mt0002743 (data as of October 1, 2026).