Public water system · 084690440
ActiveFort Thompson Water System
At a glance
Fort Thompson Water System (PWSID 084690440) is an active community water system in South Dakota. It reports serving 1,357 people through 302 service connections. Its primary water source is surface water, and EPA lists it as Native American-owned. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in April 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,357
Service connections
302
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Fort Thompson Water System compare with other water systems in South Dakota?
By EPA's size categories, Fort Thompson Water System is a small system (501 to 3,300 people). Across South Dakota, the 699 active systems average 1,387 people each. Nationally, the average active community water system reports serving 6,703 people, so Fort Thompson Water System 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. South Dakota has 510 active community water systems, 73% of the state's 699 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 24 South Dakota systems (3.4%) list surface water as their primary source.
Who owns and regulates Fort Thompson Water System?
EPA lists Fort Thompson Water System as Native American-owned. The EPA Region 08 is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act.
Does Fort Thompson Water System have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in April 2024. The violations listed here began between January 2012 and April 2024. By type: 8 monitoring and reporting, 2 contaminant level above the legal limit, 1 required treatment not met and 1 monitoring. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (4 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 |
|---|---|---|---|---|
| 2024-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2024-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2022-09-08 | Required treatment not metFailure To Address Deficiency · code 45 | Long Term 2 Enhanced Surface Water Treatment Rulecode 0800 | Yes | Resolved |
| 2022-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Resolved |
| 2021-06-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2013-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2012-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2012-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2012-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2012-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2012-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | 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.
Fort Thompson Water System: frequently asked questions
Who runs Fort Thompson Water System?
Fort Thompson Water System (PWSID 084690440) is a community water system Native American-owned. It is regulated by the EPA Region 08.
How many people does Fort Thompson Water System serve?
Fort Thompson Water System reports serving 1,357 people through 302 service connections in South Dakota.
Where does Fort Thompson Water System get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Fort Thompson Water System have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in April 2024. 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 Fort Thompson Water System'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, 3 are health-based, and the most recent began in April 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the EPA Region 08.
Where can I find Fort Thompson Water System's water quality report?
As a community water system, Fort Thompson Water System 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 South Dakota
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Sioux Falls | Minnehaha | 216,462 | Community | Surface water |
| Rapid City | Pennington | 72,009 | Community | Surface water |
| Aberdeen | Brown | 27,989 | Community | Surface water |
| Brookings Municipal Utilities | Brookings | 23,377 | Community | Groundwater |
| Watertown Municipal Utilities | Codington | 23,230 | Community | Groundwater |
| Web Water Development Association | Walworth + 9 more | 20,750 | 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, “Fort Thompson Water System, PWSID 084690440, South Dakota”, https://aquacensus.com/water-systems/south-dakota/fort-thompson-water-system-084690440 (data as of October 1, 2026).