Public water system · WI2650113
ActiveDelavan Waterworks
At a glance
Delavan Waterworks (PWSID WI2650113) is an active community water system in Walworth County, Wisconsin. It reports serving 9,028 people through 3,343 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, none is health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
9,028
Service connections
3,343
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Delavan Waterworks compare with other water systems in Walworth County?
By EPA's size categories, Delavan Waterworks is a medium system (3,301 to 10,000 people). Walworth County has 252 active public water systems, and Delavan Waterworks is the 3rd-largest of them by population served. Its population served is about 24 times the county average of 380 people per system, and accounts for 9.4% of the 95,693 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 Delavan Waterworks is about 35% 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 Delavan Waterworks?
EPA lists Delavan 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. 29 of the 252 active systems in Walworth County (12%) are also owned by a local government.
Does Delavan Waterworks have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2026. The violations listed here began between July 2000 and January 2026. By type: 9 monitoring and reporting, 2 public notice, recordkeeping or other and 1 monitoring. The contaminant or rule involved most often is Mercury (8 of them). EPA lists 11 as resolved and 1 as archived. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2026-01-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Archived |
| 2017-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2003-01-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Mercurycode 1035 | No | Resolved |
| 2002-12-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Mercurycode 1035 | No | Resolved |
| 2002-11-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Mercurycode 1035 | No | Resolved |
| 2002-10-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Mercurycode 1035 | No | Resolved |
| 2002-09-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Mercurycode 1035 | No | Resolved |
| 2002-08-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Mercurycode 1035 | No | Resolved |
| 2002-07-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Mercurycode 1035 | No | Resolved |
| 2002-05-22 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Mercurycode 1035 | No | Resolved |
| 2000-10-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2000-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | 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.
Delavan Waterworks: frequently asked questions
Who runs Delavan Waterworks?
Delavan Waterworks (PWSID WI2650113) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Delavan Waterworks serve?
Delavan Waterworks reports serving 9,028 people through 3,343 service connections in Walworth County, Wisconsin.
Where does Delavan 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 Delavan Waterworks have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2026. 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 Delavan 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, none is health-based, and the most recent began in January 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Delavan Waterworks' water quality report?
As a community water system, Delavan 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 Walworth County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Whitewater Waterworks | Walworth | 14,000 | Community | Groundwater |
| Elkhorn Waterworks | Walworth | 10,317 | Community | Groundwater |
| Lake Geneva Utility Commission | Walworth | 7,107 | Community | Groundwater |
| East Troy Waterworks | Walworth | 5,054 | Community | Groundwater |
| Bloomfield, Village of | Walworth | 4,071 | Community | Groundwater |
| Lake Como Sanitary Dist 1 | Walworth | 3,038 | 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, “Delavan Waterworks, PWSID WI2650113, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/delavan-waterworks-wi2650113 (data as of October 1, 2026).