Public water system · IL0430055
ActiveAqua Illinois-Oak Brook
At a glance
Aqua Illinois-Oak Brook (PWSID IL0430055) is an active community water system in DuPage County, Illinois. It reports serving 5,361 people through 2,021 service connections. Its primary water source is purchased surface water, and EPA lists it as privately owned. EPA's records list one violation for this system; it is not health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
5,361
Service connections
2,021
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Aqua Illinois-Oak Brook compare with other water systems in DuPage County?
By EPA's size categories, Aqua Illinois-Oak Brook is a medium system (3,301 to 10,000 people). DuPage County has 125 active public water systems. Its population served is about 22% below the county average of 6,865 people per system, and accounts for 0.6% of the 858,100 people reported by systems filed under the county. Across Illinois, the 3,872 active systems average 3,204 people each. Nationally, the average active community water system reports serving 6,703 people, so Aqua Illinois-Oak Brook is about 20% 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. Illinois has 1,773 active community water systems, 46% of the state's 3,872 active systems. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 619 Illinois systems (16%) list purchased surface water as their primary source.
Who owns and regulates Aqua Illinois-Oak Brook?
EPA lists Aqua Illinois-Oak Brook as privately owned. The IL state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 77 of the 125 active systems in DuPage County (62%) are also privately owned.
Does Aqua Illinois-Oak Brook have drinking water violations?
EPA's records list one violation for this system; it is not health-based, and the most recent began in July 2025. By type: 1 monitoring and reporting. The contaminant or rule involved is Lead and Copper Rule. EPA lists 1 as unaddressed. 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 |
|---|---|---|---|---|
| 2025-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Unaddressed |
The one violation in EPA's records.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.
Aqua Illinois-Oak Brook: frequently asked questions
Who runs Aqua Illinois-Oak Brook?
Aqua Illinois-Oak Brook (PWSID IL0430055) is a community water system privately owned. It is regulated by the IL state drinking water program.
How many people does Aqua Illinois-Oak Brook serve?
Aqua Illinois-Oak Brook reports serving 5,361 people through 2,021 service connections in DuPage County, Illinois.
Where does Aqua Illinois-Oak Brook get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Aqua Illinois-Oak Brook have any drinking water violations?
EPA's records list one violation for this system; it is not health-based, and the most recent began in July 2025. 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 Aqua Illinois-Oak Brook'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 one violation for this system; it is not health-based, and the most recent began in July 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the IL state drinking water program.
Where can I find Aqua Illinois-Oak Brook's water quality report?
As a community water system, Aqua Illinois-Oak Brook 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 DuPage County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Naperville | DuPage | 156,406 | Community | Purchased surface water |
| Wheaton | DuPage | 53,970 | Community | Purchased surface water |
| Downers Grove | DuPage | 49,425 | Community | Purchased surface water |
| Elmhurst | DuPage | 45,000 | Community | Purchased surface water |
| Lombard | DuPage | 44,476 | Community | Purchased surface water |
| Carol Stream | DuPage | 39,854 | Community | Purchased surface water |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Aqua Illinois-Oak Brook, PWSID IL0430055, Illinois”, https://aquacensus.com/water-systems/illinois/aqua-illinois-oak-brook-il0430055 (data as of October 1, 2026).