Public water system · WI1540138
ActiveWillowdale
At a glance
Willowdale (PWSID WI1540138) is an active transient non-community water system in Rock County, Wisconsin. It reports serving 55 people through 1 service connection. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 10 violations for this system; 8 are health-based, and the most recent began in September 2008.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
55
Service connections
1
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Willowdale compare with other water systems in Rock County?
By EPA's size categories, Willowdale is a very small system (500 people or fewer). Rock County has 156 active public water systems. Its population served is well below the county average of 952 people per system, and accounts for less than 0.1% of the 148,563 people reported by systems filed under the county. Across Wisconsin, the 11,056 active systems average 469 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Willowdale is about 62% below that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. Wisconsin has 9,112 active transient non-community water systems, 82% 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 Willowdale?
EPA lists Willowdale as privately owned. 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. 126 of the 156 active systems in Rock County (81%) are also privately owned.
Does Willowdale have drinking water violations?
EPA's records list 10 violations for this system; 8 are health-based, and the most recent began in September 2008. The violations listed here began between October 1994 and September 2008. By type: 8 contaminant level above the legal limit, 1 public notice, recordkeeping or other and 1 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (9 of them). EPA lists 10 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 |
|---|---|---|---|---|
| 2008-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2006-10-11 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2006-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1997-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1995-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1994-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1994-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1994-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
All 10 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.
Willowdale: frequently asked questions
Who runs Willowdale?
Willowdale (PWSID WI1540138) is a transient non-community water system privately owned. It is regulated by the WI state drinking water program.
How many people does Willowdale serve?
Willowdale reports serving 55 people through 1 service connection in Rock County, Wisconsin.
Where does Willowdale 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 Willowdale have any drinking water violations?
EPA's records list 10 violations for this system; 8 are health-based, and the most recent began in September 2008. 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 Willowdale's 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 10 violations for this system; 8 are health-based, and the most recent began in September 2008. For current results, consult EPA ECHO, or the WI state drinking water program.
Where can I find Willowdale's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Willowdale is a transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
Other water systems in Rock County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Janesville Water Utility | Rock | 64,415 | Community | Groundwater |
| Beloit City of | Rock | 36,677 | Community | Groundwater |
| Evansville Waterworks | Rock | 5,703 | Community | Groundwater |
| Milton Waterworks | Rock | 5,588 | Community | Groundwater |
| Edgerton Waterworks | Rock | 5,512 | Community | Groundwater |
| Wi Dot Rest Area 22 Turtle | Rock | 3,005 | 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, “Willowdale, PWSID WI1540138, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/willowdale-wi1540138 (data as of October 1, 2026).