Public water system · WI2410172

Active

Oak Creek Waterworks

At a glance

Oak Creek Waterworks (PWSID WI2410172) is an active community water system in Milwaukee County, Wisconsin. It reports serving 32,104 people through 11,890 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in October 2024.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO public records.

Population served

32,104

Service connections

11,890

Primary source

Surface water

System type

CWS

Community water system

System record

PWSIDWI2410172

System typeCommunity water system

Activity statusActive

Population served32,104

Service connections11,890

Primary water sourceSurface water

Owner typeLocal government

Primacy agencyWI state drinking water program

City servedOak Creek

StateWisconsin

ZIP—

CountyMilwaukee County

How does Oak Creek Waterworks compare with other water systems in Milwaukee County?

By EPA's size categories, Oak Creek Waterworks is a large system (10,001 to 100,000 people). Milwaukee County has 85 active public water systems, and Oak Creek Waterworks is the 5th-largest of them by population served. Its population served is about 186% above the county average of 11,209 people per system, and accounts for 3.4% of the 952,731 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 Oak Creek Waterworks is about 4.8 times 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. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 20 Wisconsin systems (0.2%) list surface water as their primary source.

Who owns and regulates Oak Creek Waterworks?

EPA lists Oak Creek 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 85 active systems in Milwaukee County (31%) are also owned by a local government.

Does Oak Creek Waterworks have drinking water violations?

Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in October 2024. The violations listed here began between October 2013 and October 2024. By type: 6 monitoring and reporting, 4 contaminant level above the legal limit, 1 public notice, recordkeeping or other and 1 required treatment not met. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (7 of them). EPA lists 11 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
2024-10-17	Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75	Public Noticecode 7500	No	Unaddressed
2024-10-17	Required treatment not metLSL Inventory · code 2E	Lead and Copper Rule Revisionscode 5200	Yes	Resolved
2021-01-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Total trihalomethanes (TTHM)code 2950	No	Resolved
2021-01-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Haloacetic acids (HAA5)code 2456	No	Resolved
2019-01-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2018-10-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2018-07-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2018-04-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2014-01-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Haloacetic acids (HAA5)code 2456	No	Resolved
2014-01-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Total trihalomethanes (TTHM)code 2950	No	Resolved
2013-10-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Total trihalomethanes (TTHM)code 2950	No	Resolved
2013-10-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Haloacetic acids (HAA5)code 2456	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.

Oak Creek Waterworks: frequently asked questions

Who runs Oak Creek Waterworks?

Oak Creek Waterworks (PWSID WI2410172) is a community water system owned by a local government. It is regulated by the WI state drinking water program.

How many people does Oak Creek Waterworks serve?

Oak Creek Waterworks reports serving 32,104 people through 11,890 service connections in Milwaukee County, Wisconsin.

Where does Oak Creek Waterworks get its water?

EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.

Does Oak Creek Waterworks have any drinking water violations?

Of the 12 most recent violations in EPA's records, 5 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 Oak Creek 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, 5 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 Oak Creek Waterworks' water quality report?

As a community water system, Oak Creek 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 Milwaukee County

Water system	County	Population served	Type	Source
Milwaukee Waterworks	Milwaukee	626,000	Community	Surface water
West Allis Waterworks	Milwaukee	63,240	Community	Purchased surface water
Wauwatosa Waterworks	Milwaukee	49,064	Community	Purchased surface water
North Shore Water Commission	Milwaukee	35,598	Community	Surface water
Franklin Water Utility	Milwaukee	22,500	Community	Purchased surface water
South Milwaukee Waterworks	Milwaukee	21,340	Community	Surface water

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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, “Oak Creek Waterworks, PWSID WI2410172, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/oak-creek-waterworks-wi2410172 (data as of October 1, 2026).