Public water system · MT0001398
ActiveCardwell School Dist 16 and 31
At a glance
Cardwell School Dist 16 and 31 (PWSID MT0001398) is an active non-transient non-community water system in Jefferson County, Montana. It reports serving 63 people through 1 service connection. Its primary water source is groundwater, and EPA lists it as owned by a state government. Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in December 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
63
Service connections
1
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Cardwell School Dist 16 and 31 compare with other water systems in Jefferson County?
By EPA's size categories, Cardwell School Dist 16 and 31 is a very small system (500 people or fewer). Jefferson County has 41 active public water systems. Its population served is well below the county average of 241 people per system, and accounts for 0.6% of the 9,886 people reported by systems filed under the county. Across Montana, the 2,378 active systems average 489 people each. Nationally, the average active non-transient non-community water system reports serving 430 people, so Cardwell School Dist 16 and 31 is well below that figure.
What does “non-transient non-community water system” mean?
A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. Montana has 319 active non-transient non-community water systems, 13% 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 Cardwell School Dist 16 and 31?
EPA lists Cardwell School Dist 16 and 31 as owned by a state 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. 6 of the 41 active systems in Jefferson County (15%) are also owned by a state government.
Does Cardwell School Dist 16 and 31 have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in December 2025. The violations listed here began between January 2014 and December 2025. By type: 7 monitoring and reporting, 3 monitoring, 1 required treatment not met and 1 reporting. The contaminant or rule involved most often is Revised Total Coliform Rule (5 of them). EPA lists 10 as resolved, 1 as unaddressed 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement. 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 |
|---|---|---|---|---|
| 2025-12-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2024-06-01 | Required treatment not metTreatment Technique Startup Procedures (RTCR) · code 2D | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Archived |
| 2019-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2019-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2018-09-02 | ReportingReport Startup Procedures Cert Form (RTCR) · code 4C | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2017-09-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Resolved |
| 2016-09-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2014-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Antimonycode 1074 | No | Resolved |
| 2014-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nickelcode 1036 | 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.
Cardwell School Dist 16 and 31: frequently asked questions
Who runs Cardwell School Dist 16 and 31?
Cardwell School Dist 16 and 31 (PWSID MT0001398) is a non-transient non-community water system owned by a state government. It is regulated by the MT state drinking water program.
How many people does Cardwell School Dist 16 and 31 serve?
Cardwell School Dist 16 and 31 reports serving 63 people through 1 service connection in Jefferson County, Montana.
Where does Cardwell School Dist 16 and 31 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 Cardwell School Dist 16 and 31 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 December 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 Cardwell School Dist 16 and 31'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 December 2025. For current results, consult EPA ECHO, or the MT state drinking water program.
Where can I find Cardwell School Dist 16 and 31's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Cardwell School Dist 16 and 31 is a non-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 Jefferson County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Whitehall Town of | Jefferson | 1,500 | Community | Groundwater |
| Boulder City of | Jefferson | 1,400 | Community | Groundwater |
| Jefferson Hills Wua | Jefferson | 780 | Community | Groundwater |
| Lewis and Clark Caverns Visitor Center | Jefferson | 615 | Transient non-community | Groundwater under influence of surface water |
| Jefferson City South Rest Stop | Jefferson | 600 | Transient non-community | Groundwater |
| Montana City School Dist 27 | Jefferson | 534 | Non-transient non-community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Cardwell School Dist 16 and 31, PWSID MT0001398, Montana”, https://aquacensus.com/water-systems/montana/cardwell-school-dist-16-and-31-mt0001398 (data as of October 1, 2026).