Public water system · WI7370169
ActiveColby Waterworks
At a glance
Colby Waterworks (PWSID WI7370169) is an active community water system in Marathon County, Wisconsin. It reports serving 1,829 people through 700 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list one violation for this system; it is not health-based, and the most recent began in March 1992.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,829
Service connections
700
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Colby Waterworks compare with other water systems in Marathon County?
By EPA's size categories, Colby Waterworks is a small system (501 to 3,300 people). Marathon County has 196 active public water systems. Its population served is about 3.5 times the county average of 528 people per system, and accounts for 1.8% 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 Colby Waterworks 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 Colby Waterworks?
EPA lists Colby 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 Colby Waterworks have drinking water violations?
EPA's records list one violation for this system; it is not health-based, and the most recent began in March 1992. By type: 1 monitoring and reporting. The contaminant or rule involved is Total coliform bacteria (TCR). EPA lists 1 as archived. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 1992-03-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
The one violation in EPA's records.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.
Colby Waterworks: frequently asked questions
Who runs Colby Waterworks?
Colby Waterworks (PWSID WI7370169) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Colby Waterworks serve?
Colby Waterworks reports serving 1,829 people through 700 service connections in Marathon County, Wisconsin.
Where does Colby 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 Colby Waterworks have any drinking water violations?
EPA's records list one violation for this system; it is not health-based, and the most recent began in March 1992. 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 Colby 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 one violation for this system; it is not health-based, and the most recent began in March 1992. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Colby Waterworks' water quality report?
As a community water system, Colby 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 |
| Mosinee Waterworks | Marathon | 3,406 | Community | Groundwater |
| Rothschild Waterworks | Marathon | 3,190 | 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, “Colby Waterworks, PWSID WI7370169, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/colby-waterworks-wi7370169 (data as of October 1, 2026).