Public water system · WI1130218
ActiveCottage Grove Waterworks
At a glance
Cottage Grove Waterworks (PWSID WI1130218) is an active community water system in Dane County, Wisconsin. It reports serving 9,345 people through 3,461 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
9,345
Service connections
3,461
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Cottage Grove Waterworks compare with other water systems in Dane County?
By EPA's size categories, Cottage Grove Waterworks is a medium system (3,301 to 10,000 people). Dane County has 300 active public water systems. Its population served is about 5.4 times the county average of 1,742 people per system, and accounts for 1.8% of the 522,696 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 Cottage Grove Waterworks is about 39% above 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 Cottage Grove Waterworks?
EPA lists Cottage Grove 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. 74 of the 300 active systems in Dane County (25%) are also owned by a local government.
Does Cottage Grove Waterworks have drinking water violations?
EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in October 2024. The violations listed here began between September 1991 and October 2024. By type: 3 monitoring and reporting, 1 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 Total coliform bacteria (TCR) (4 of them). EPA lists 3 as resolved, 2 as archived 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. 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. 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 |
|---|---|---|---|---|
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Resolved |
| 2024-10-17 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 1997-02-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1994-12-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1994-12-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1991-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
All 6 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.
Cottage Grove Waterworks: frequently asked questions
Who runs Cottage Grove Waterworks?
Cottage Grove Waterworks (PWSID WI1130218) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Cottage Grove Waterworks serve?
Cottage Grove Waterworks reports serving 9,345 people through 3,461 service connections in Dane County, Wisconsin.
Where does Cottage Grove 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 Cottage Grove Waterworks have any drinking water violations?
EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in October 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 Cottage Grove 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 6 violations for this system; 2 are health-based, and the most recent began in October 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 Cottage Grove Waterworks' water quality report?
As a community water system, Cottage Grove 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 Dane County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Madison Water Utility | Dane | 272,000 | Community | Groundwater |
| Sun Prairie Utilities | Dane | 39,300 | Community | Groundwater |
| Fitchburg Utility Dist 1 | Dane | 24,500 | Community | Groundwater |
| Middleton Waterworks | Dane | 23,868 | Community | Groundwater |
| Waunakee Waterworks | Dane | 14,879 | Community | Groundwater |
| Verona Waterworks | Dane | 14,030 | 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, “Cottage Grove Waterworks, PWSID WI1130218, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/cottage-grove-waterworks-wi1130218 (data as of October 1, 2026).