Public water system · WI7440129
ActiveThree Lakes Sanitary District
At a glance
Three Lakes Sanitary District (PWSID WI7440129) is an active community water system in Oneida County, Wisconsin. It reports serving 500 people through 283 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in July 2025.
This page covers its drinking water system only; sewer and wastewater service are not part of EPA's drinking water records.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
500
Service connections
283
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Three Lakes Sanitary District compare with other water systems in Oneida County?
By EPA's size categories, Three Lakes Sanitary District is a very small system (500 people or fewer). Oneida County has 345 active public water systems, and Three Lakes Sanitary District is the 4th-largest of them by population served. Its population served is about 4.3 times the county average of 117 people per system, and accounts for 1.2% of the 40,498 people reported by systems filed under the county. Across Wisconsin, the 11,056 active systems average 469 people each. Nationally, the average active community water system reports serving 6,703 people, so Three Lakes Sanitary District 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. Wisconsin has 1,053 active community water systems, 9.5% of the state's 11,056 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 10,978 Wisconsin systems (99%) list groundwater as their primary source.
Who owns and regulates Three Lakes Sanitary District?
EPA lists Three Lakes Sanitary District as owned by a local government. The WI state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 15 of the 345 active systems in Oneida County (4.3%) are also owned by a local government.
Does Three Lakes Sanitary District have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in July 2025. The violations listed here began between August 2008 and July 2025. By type: 3 public notice, recordkeeping or other, 3 monitoring, 2 required treatment not met, 2 monitoring and reporting, 1 reporting and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Revised Total Coliform Rule (3 of them). EPA lists 10 as resolved and 2 as unaddressed. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2025-03-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2025-01-16 | Required treatment not metFailure To Address Deficiency · code 45 | Groundwater Rulecode 0700 | Yes | Resolved |
| 2024-10-17 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Resolved |
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Resolved |
| 2024-10-17 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 2024-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2022-12-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-11-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2021-02-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2008-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | 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.
Three Lakes Sanitary District: frequently asked questions
Who runs Three Lakes Sanitary District?
Three Lakes Sanitary District (PWSID WI7440129) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Three Lakes Sanitary District serve?
Three Lakes Sanitary District reports serving 500 people through 283 service connections in Oneida County, Wisconsin.
Where does Three Lakes Sanitary District 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 Three Lakes Sanitary District 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 July 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 Three Lakes Sanitary District'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 July 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Three Lakes Sanitary District's water quality report?
As a community water system, Three Lakes Sanitary District 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 Oneida County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Rhinelander Water & Wastewater | Oneida | 8,234 | Community | Groundwater |
| Lakeland Sanitary Dist 1 | Oneida | 2,381 | Community | Groundwater |
| Minocqua Hazelhurst Elem Sch | Oneida | 650 | Non-transient non-community | Groundwater |
| Scouting America Camp Tesomas Program Center and Dining Hall | Oneida | 500 | Transient non-community | Groundwater |
| Wi Dnr Clear Lk Cmpgd 8 | Oneida | 450 | Transient non-community | Groundwater |
| Wi Dnr Clear Lk Cmpgd 24 | Oneida | 450 | 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, “Three Lakes Sanitary District, PWSID WI7440129, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/three-lakes-sanitary-district-wi7440129 (data as of October 1, 2026).