Public water system · WI7370159
ActiveMosinee Waterworks
At a glance
Mosinee Waterworks (PWSID WI7370159) is an active community water system in Marathon County, Wisconsin. It reports serving 3,406 people through 1,783 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 8 violations for this system; 2 are health-based, and the most recent began in July 2017.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
3,406
Service connections
1,783
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Mosinee Waterworks compare with other water systems in Marathon County?
By EPA's size categories, Mosinee Waterworks is a medium system (3,301 to 10,000 people). Marathon County has 196 active public water systems, and Mosinee Waterworks is the 5th-largest of them by population served. Its population served is about 6.5 times the county average of 528 people per system, and accounts for 3.3% of the 103,490 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 Mosinee Waterworks is about half of 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 Mosinee Waterworks?
EPA lists Mosinee Waterworks 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. 43 of the 196 active systems in Marathon County (22%) are also owned by a local government.
Does Mosinee Waterworks have drinking water violations?
EPA's records list 8 violations for this system; 2 are health-based, and the most recent began in July 2017. The violations listed here began between July 1996 and July 2017. By type: 4 monitoring and reporting, 2 public notice, recordkeeping or other and 2 required treatment not met. The contaminant or rule involved most often is Lead and Copper Rule (5 of them). EPA lists 7 as resolved and 1 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 |
|---|---|---|---|---|
| 2017-07-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2017-07-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2014-01-01 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2013-04-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2013-01-01 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 2012-10-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2005-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Bromatecode 1011 | No | Resolved |
| 1996-07-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
All 8 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.
Mosinee Waterworks: frequently asked questions
Who runs Mosinee Waterworks?
Mosinee Waterworks (PWSID WI7370159) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Mosinee Waterworks serve?
Mosinee Waterworks reports serving 3,406 people through 1,783 service connections in Marathon County, Wisconsin.
Where does Mosinee Waterworks 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 Mosinee Waterworks have any drinking water violations?
EPA's records list 8 violations for this system; 2 are health-based, and the most recent began in July 2017. 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 Mosinee Waterworks' 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. EPA's records list 8 violations for this system; 2 are health-based, and the most recent began in July 2017. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Mosinee Waterworks' water quality report?
As a community water system, Mosinee Waterworks 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 Marathon County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Wausau Waterworks | Marathon | 39,994 | Community | Groundwater |
| Weston Municipal Utilities | Marathon | 16,000 | Community | Groundwater |
| Kronenwetter Water & Sewer Utility | Marathon | 6,931 | Community | Groundwater |
| Rib Mountain Water Utility | Marathon | 6,398 | Community | Groundwater |
| Rothschild Waterworks | Marathon | 3,190 | Community | Groundwater |
| Abbotsford Waterworks | Marathon | 2,502 | 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, “Mosinee Waterworks, PWSID WI7370159, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/mosinee-waterworks-wi7370159 (data as of October 1, 2026).