Public water system · WI4200475
ActiveOakfield Waterworks
At a glance
Oakfield Waterworks (PWSID WI4200475) is an active community water system in Fond du Lac County, Wisconsin. It reports serving 1,058 people through 391 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 9 violations for this system; none is health-based, and the most recent began in October 2019.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,058
Service connections
391
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Oakfield Waterworks compare with other water systems in Fond du Lac County?
By EPA's size categories, Oakfield Waterworks is a small system (501 to 3,300 people). Fond du Lac County has 207 active public water systems, and Oakfield Waterworks is the 5th-largest of them by population served. Its population served is about 151% above the county average of 421 people per system, and accounts for 1.2% of the 87,145 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 Oakfield 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 Oakfield Waterworks?
EPA lists Oakfield 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. 26 of the 207 active systems in Fond du Lac County (13%) are also owned by a local government.
Does Oakfield Waterworks have drinking water violations?
EPA's records list 9 violations for this system; none is health-based, and the most recent began in October 2019. The violations listed here began between November 1996 and October 2019. By type: 7 monitoring and reporting, 1 monitoring and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Lead and Copper Rule (2 of them). EPA lists 8 as resolved 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. 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 |
|---|---|---|---|---|
| 2019-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2012-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2010-10-01 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 2008-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1998-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1996-11-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
All 9 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.
Oakfield Waterworks: frequently asked questions
Who runs Oakfield Waterworks?
Oakfield Waterworks (PWSID WI4200475) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Oakfield Waterworks serve?
Oakfield Waterworks reports serving 1,058 people through 391 service connections in Fond du Lac County, Wisconsin.
Where does Oakfield 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 Oakfield Waterworks have any drinking water violations?
EPA's records list 9 violations for this system; none is health-based, and the most recent began in October 2019. 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 Oakfield 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 9 violations for this system; none is health-based, and the most recent began in October 2019. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Oakfield Waterworks' water quality report?
As a community water system, Oakfield 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 Fond du Lac County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Fond Du Lac Waterworks | Fond du Lac | 44,678 | Community | Groundwater |
| Ripon Water Utility | Fond du Lac | 7,716 | Community | Groundwater |
| North Fond Du Lac Waterworks | Fond du Lac | 5,414 | Community | Groundwater |
| Campbellsport Waterworks | Fond du Lac | 1,825 | Community | Groundwater |
| Ashwood Grove Edgewater | Fond du Lac | 1,046 | Community | Groundwater |
| Fond Du Lac Tn Water Utility | Fond du Lac | 980 | Community | Purchased 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, “Oakfield Waterworks, PWSID WI4200475, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/oakfield-waterworks-wi4200475 (data as of October 1, 2026).