Public water system · MN1740008
ActiveThompson Oaks
At a glance
Thompson Oaks (PWSID MN1740008) is an active community water system in Steele County, Minnesota. It reports serving 51 people through 17 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, 9 are health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
51
Service connections
17
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Thompson Oaks compare with other water systems in Steele County?
By EPA's size categories, Thompson Oaks is a very small system (500 people or fewer). Steele County has 35 active public water systems. Its population served is well below the county average of 1,024 people per system, and accounts for 0.1% of the 35,842 people reported by systems filed under the county. Across Minnesota, the 6,465 active systems average 820 people each. Nationally, the average active community water system reports serving 6,703 people, so Thompson Oaks 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. Minnesota has 987 active community water systems, 15% of the state's 6,465 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 6,261 Minnesota systems (97%) list groundwater as their primary source.
Who owns and regulates Thompson Oaks?
EPA lists Thompson Oaks as privately owned. The MN state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 26 of the 35 active systems in Steele County (74%) are also privately owned.
Does Thompson Oaks have drinking water violations?
Of the 12 most recent violations in EPA's records, 9 are health-based, and the most recent began in January 2026. The violations listed here began between April 2020 and January 2026. By type: 9 contaminant level above the legal limit, 2 monitoring and reporting and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Gross alpha (excluding radon and uranium) (10 of them). EPA lists 7 as archived and 5 as resolved. 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. 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 |
|---|---|---|---|---|
| 2026-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | Yes | Archived |
| 2025-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | Yes | Archived |
| 2025-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | Yes | Archived |
| 2025-04-28 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2025-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | Yes | Archived |
| 2025-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | Yes | Archived |
| 2024-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | Yes | Archived |
| 2023-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Resolved |
| 2023-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | No | Resolved |
| 2023-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | Yes | Archived |
| 2020-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | Yes | Resolved |
| 2020-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Gross alpha (excluding radon and uranium)code 4000 | 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.
Thompson Oaks: frequently asked questions
Who runs Thompson Oaks?
Thompson Oaks (PWSID MN1740008) is a community water system privately owned. It is regulated by the MN state drinking water program.
How many people does Thompson Oaks serve?
Thompson Oaks reports serving 51 people through 17 service connections in Steele County, Minnesota.
Where does Thompson Oaks 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 Thompson Oaks have any drinking water violations?
Of the 12 most recent violations in EPA's records, 9 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 Thompson Oaks' 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, 9 are health-based, and the most recent began in January 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the MN state drinking water program.
Where can I find Thompson Oaks' water quality report?
As a community water system, Thompson Oaks 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 Steele County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Owatonna | Steele | 26,430 | Community | Groundwater |
| Blooming Prairie | Steele | 1,987 | Community | Groundwater |
| Straight River Rest Area South Mndot | Steele | 1,893 | Transient non-community | Groundwater |
| Straight River Rest Area North Mndot | Steele | 1,206 | Transient non-community | Groundwater |
| Medford | Steele | 1,200 | Community | Groundwater |
| Ellendale | Steele | 636 | 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, “Thompson Oaks, PWSID MN1740008, Minnesota”, https://aquacensus.com/water-systems/minnesota/thompson-oaks-mn1740008 (data as of October 1, 2026).