Public water system · WI1540116
ActiveOakhill Waterworks
At a glance
Oakhill Waterworks (PWSID WI1540116) is an active community water system in Rock County, Wisconsin. It reports serving 130 people through 45 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2015.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
130
Service connections
45
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Oakhill Waterworks compare with other water systems in Rock County?
By EPA's size categories, Oakhill Waterworks 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 community water system reports serving 6,703 people, so Oakhill 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 Oakhill Waterworks?
EPA lists Oakhill Waterworks 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 Oakhill 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 July 2015. The violations listed here began between January 1998 and July 2015. By type: 6 public notice, recordkeeping or other and 6 monitoring and reporting. The contaminant or rule involved most often is Consumer Confidence Rule (5 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 |
|---|---|---|---|---|
| 2015-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2013-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2010-10-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2008-07-01 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2008-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2007-10-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2007-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2006-10-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2002-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 1998-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | 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.
Oakhill Waterworks: frequently asked questions
Who runs Oakhill Waterworks?
Oakhill Waterworks (PWSID WI1540116) is a community water system privately owned. It is regulated by the WI state drinking water program.
How many people does Oakhill Waterworks serve?
Oakhill Waterworks reports serving 130 people through 45 service connections in Rock County, Wisconsin.
Where does Oakhill 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 Oakhill 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 July 2015. 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 Oakhill 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 July 2015. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Oakhill Waterworks' water quality report?
As a community water system, Oakhill 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 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, “Oakhill Waterworks, PWSID WI1540116, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/oakhill-waterworks-wi1540116 (data as of October 1, 2026).