Public Water System

Thompson Oaks

PWSID MN1740008 · Minnesota · 51 people served

Failing

Thompson Oaks is an EPA-regulated public water system in Minnesota (PWSID MN1740008). It serves an estimated 51 residents — a rural community of customers — across 1 community across 1 ZIP code.

Over the past five years, Thompson Oaks has recorded 22 EPA health-based violations. The grade of F summarizes this compliance pattern. Specific contaminants, dates, and rule citations are listed in the violation history below.

Service Area

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Centered on the averaged ZIP-code centroid of 1 ZIP served.

Population

Cities

ZIPs

Violations

EPA Health-Based Violations

Health-based Maximum Contaminant Level (MCL) violations on file for Thompson Oaks over the past five years of EPA SDWIS reporting.

Radiumradiological

EPA Code 4000 · Maximum Contaminant Level Exceedance

violations

EPA Limit

5 pCi/L

Last Reading

19.5 PCI/L

First Reported

Jan 2023

Most Recent

Oct 2025

What this violation means

Radium-226 and Radium-228 occur naturally in groundwater, particularly in regions with granite or sandstone aquifers. Long-term ingestion increases the risk of bone, sinus, and other cancers because radium concentrates in bone tissue.

Recommended precautions

→Reverse osmosis and ion exchange (water softeners) remove radium.
→Boiling does NOT remove radium and may concentrate it.
→Private well users in radium-rich geology should test every 3–5 years.

Read the complete guide to Radium

Source: EPA Safe Drinking Water Information System (SDWIS). Health-based violations only. Older violations may have been resolved; check your utility's most recent Consumer Confidence Report for current status.

Cities Served by Thompson Oaks

Ellendale

ZIP Codes Served

56026

About this system

EPA records this system as PWSID MN1740008. Data reflects the most recent EPA SDWIS publication as of 2026-05-18. Public Water System Identifiers (PWSIDs) are assigned by the EPA's Safe Drinking Water Act program to track every regulated water utility in the United States. The first two letters typically indicate the state primacy agency. For real-time water quality information, contact Thompson Oaks directly or review their annual Consumer Confidence Report (CCR).