Public water system · WI6170267
ActiveKnapp Waterworks
At a glance
Knapp Waterworks (PWSID WI6170267) is an active community water system in Dunn County, Wisconsin. It reports serving 486 people through 229 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, one is health-based, and the most recent began in September 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
486
Service connections
229
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Knapp Waterworks compare with other water systems in Dunn County?
By EPA's size categories, Knapp Waterworks is a very small system (500 people or fewer). Dunn County has 86 active public water systems, and Knapp Waterworks is the 6th-largest of them by population served. Its population served is about 60% above the county average of 305 people per system, and accounts for 1.9% of the 26,187 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 Knapp 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 Knapp Waterworks?
EPA lists Knapp 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. 15 of the 86 active systems in Dunn County (17%) are also owned by a local government.
Does Knapp Waterworks have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in September 2025. The violations listed here began between October 2013 and September 2025. By type: 8 monitoring and reporting, 3 monitoring and 1 required treatment not met. The contaminant or rule involved most often is Revised Total Coliform Rule (3 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 |
|---|---|---|---|---|
| 2025-09-02 | Required treatment not metTreatment Technique No Certif. Operator · code 12 | Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400 | Yes | Resolved |
| 2024-04-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2023-08-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2023-02-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-09-09 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2020-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2020-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2017-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2017-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2016-06-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2013-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | 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.
Knapp Waterworks: frequently asked questions
Who runs Knapp Waterworks?
Knapp Waterworks (PWSID WI6170267) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Knapp Waterworks serve?
Knapp Waterworks reports serving 486 people through 229 service connections in Dunn County, Wisconsin.
Where does Knapp 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 Knapp Waterworks have any drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in September 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 Knapp 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, one is health-based, and the most recent began in September 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 Knapp Waterworks' water quality report?
As a community water system, Knapp 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 Dunn County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Menomonie Waterworks | Dunn | 15,950 | Community | Groundwater |
| Colfax Waterworks | Dunn | 1,102 | Community | Groundwater |
| Boyceville Waterworks | Dunn | 1,043 | Community | Groundwater |
| Elk Mound Waterworks | Dunn | 895 | Community | Groundwater |
| Birch Terrace Mobile Home Community | Dunn | 700 | Community | Groundwater |
| Synergy Cooperative - Ridgeland | Dunn | 475 | 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, “Knapp Waterworks, PWSID WI6170267, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/knapp-waterworks-wi6170267 (data as of October 1, 2026).