Public water system · WI1280044
ActiveWatertown Waterworks
At a glance
Watertown Waterworks (PWSID WI1280044) is an active community water system in Jefferson County, Wisconsin. It reports serving 23,945 people through 8,708 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 7 violations for this system; 5 are health-based, and the most recent began in January 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
23,945
Service connections
8,708
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Watertown Waterworks compare with other water systems in Jefferson County?
By EPA's size categories, Watertown Waterworks is a large system (10,001 to 100,000 people). Jefferson County has 195 active public water systems, and Watertown Waterworks is the largest of them by population served. Its population served is about 53 times the county average of 453 people per system, and accounts for 27% of the 88,343 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 Watertown Waterworks is about 3.6 times 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 Watertown Waterworks?
EPA lists Watertown 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. 34 of the 195 active systems in Jefferson County (17%) are also owned by a local government.
Does Watertown Waterworks have drinking water violations?
EPA's records list 7 violations for this system; 5 are health-based, and the most recent began in January 2024. The violations listed here began between May 1996 and January 2024. By type: 5 contaminant level above the legal limit and 2 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (5 of them). EPA lists 7 as resolved. 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 |
|---|---|---|---|---|
| 2024-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2024-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2004-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2001-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1997-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
All 7 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.
Watertown Waterworks: frequently asked questions
Who runs Watertown Waterworks?
Watertown Waterworks (PWSID WI1280044) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Watertown Waterworks serve?
Watertown Waterworks reports serving 23,945 people through 8,708 service connections in Jefferson County, Wisconsin.
Where does Watertown 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 Watertown Waterworks have any drinking water violations?
EPA's records list 7 violations for this system; 5 are health-based, and the most recent began in January 2024. 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 Watertown 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 7 violations for this system; 5 are health-based, and the most recent began in January 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Watertown Waterworks' water quality report?
As a community water system, Watertown 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 Jefferson County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Fort Atkinson Waterworks | Jefferson | 12,390 | Community | Groundwater |
| Jefferson Waterworks | Jefferson | 7,926 | Community | Groundwater |
| Lake Mills Waterworks | Jefferson | 6,211 | Community | Groundwater |
| Waterloo Waterworks | Jefferson | 3,520 | Community | Groundwater |
| Johnson Creek Waterworks | Jefferson | 3,318 | Community | Groundwater |
| Wi Dot Rest Area 13 Aztalan | Jefferson | 1,904 | 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, “Watertown Waterworks, PWSID WI1280044, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/watertown-waterworks-wi1280044 (data as of October 1, 2026).