Public water system · WI1280115
ActiveWaterloo Waterworks
At a glance
Waterloo Waterworks (PWSID WI1280115) is an active community water system in Jefferson County, Wisconsin. It reports serving 3,520 people through 1,303 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, 4 are health-based, and the most recent began in October 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
3,520
Service connections
1,303
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Waterloo Waterworks compare with other water systems in Jefferson County?
By EPA's size categories, Waterloo Waterworks is a medium system (3,301 to 10,000 people). Jefferson County has 195 active public water systems, and Waterloo Waterworks is the 5th-largest of them by population served. Its population served is about 7.8 times the county average of 453 people per system, and accounts for 4% 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 Waterloo 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 Waterloo Waterworks?
EPA lists Waterloo 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 Waterloo Waterworks have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in October 2023. The violations listed here began between September 1993 and October 2023. By type: 7 monitoring and reporting, 3 required treatment not met, 1 public notice, recordkeeping or other and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Lead and Copper Rule (10 of them). EPA lists 12 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 |
|---|---|---|---|---|
| 2023-10-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2019-10-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2018-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2018-01-01 | Required treatment not metLead Service Line Replacement (LSLR) · code 64 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2018-01-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2017-06-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2017-06-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2017-06-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2017-06-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2007-07-01 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2006-01-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1993-09-01 | 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.
Waterloo Waterworks: frequently asked questions
Who runs Waterloo Waterworks?
Waterloo Waterworks (PWSID WI1280115) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Waterloo Waterworks serve?
Waterloo Waterworks reports serving 3,520 people through 1,303 service connections in Jefferson County, Wisconsin.
Where does Waterloo 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 Waterloo Waterworks have any drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in October 2023. 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 Waterloo 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. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in October 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Waterloo Waterworks' water quality report?
As a community water system, Waterloo 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 |
|---|---|---|---|---|
| Watertown Waterworks | Jefferson | 23,945 | Community | Groundwater |
| Fort Atkinson Waterworks | Jefferson | 12,390 | Community | Groundwater |
| Jefferson Waterworks | Jefferson | 7,926 | Community | Groundwater |
| Lake Mills Waterworks | Jefferson | 6,211 | 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, “Waterloo Waterworks, PWSID WI1280115, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/waterloo-waterworks-wi1280115 (data as of October 1, 2026).