IL0430700 · Illinois
OAK BROOK
Federal fiscal 2026Q3 · EPA violation and follow-up records
- Violation records shown
- 3
- EPA health-based flag
- 0
- Health-based records unresolved in this snapshot
- 0
- Monitoring and reporting records
- 2
Counties listed by EPA · DuPage County, Illinois
Find the utility’s annual water quality report. For current advisories, check the utility or local drinking-water authority.
Violations and what followed
Among 3 resolved records with both dates, the median interval from recorded noncompliance start to EPA’s return-to-compliance date was 149 days. The interval uses the reporting periods and dates on file.
Other or unclassified · Resolved
Consumer Confidence Report Inadequate ReportingViolation 7118610 · Consumer Confidence Rule · Consumer Confidence RuleNoncompliance period start July 1, 2024 · period end June 11, 2025 · first reported November 21, 2024 · EPA return-to-compliance field June 11, 2025
2 linked actions
Enforcement and resolution records linked by EPA Action ID Date Category EPA action type 1137412 November 1, 2024 Informal State Violation/Reminder Notice 1137414 June 11, 2025 Resolving State Compliance achieved Monitoring or reporting · Resolved
Monitoring and Reporting (DBP)Violation 7118609 · Total Haloacetic Acids (HAA5) · Stage 2 Disinfectants and Disinfection Byproducts RuleNoncompliance period start July 1, 2024 · period end September 30, 2024 · first reported November 21, 2024 · EPA return-to-compliance field September 30, 2024
4 linked actions
Enforcement and resolution records linked by EPA Action ID Date Category EPA action type 1137410 October 15, 2024 Informal State Violation/Reminder Notice 1137411 October 15, 2024 Informal State Public Notification requested 1137413 November 13, 2024 Resolving State Compliance achieved 1137415 June 23, 2025 Informal State Public Notification received Monitoring or reporting · Resolved
Follow-up Or Routine LCR Tap M/RViolation 7118608 · Lead and Copper Rule · Lead and Copper RuleNoncompliance period start October 1, 2023 · period end February 27, 2024 · first reported February 14, 2024 · EPA return-to-compliance field February 27, 2024
4 linked actions
Enforcement and resolution records linked by EPA Action ID Date Category EPA action type 1137406 October 11, 2023 Informal State Violation/Reminder Notice 1137407 October 11, 2023 Informal State Public Notification requested 1137408 February 27, 2024 Resolving State Compliance achieved 1137409 October 2, 2024 Informal State Public Notification received
EPA data and scope
How to read the records
The enforcement snapshot is federal fiscal 2026Q3. The EPA archive labels its violation file October 13, 2026. EPA says federal reporting can lag by several months. For current advisories, check your utility or local drinking-water authority.
- We matched active community water systems by public water system ID between EPA’s system search and SDWIS inventory. We show violations with a recorded noncompliance, initial reporting or return-to-compliance date from 2021 onward, plus earlier records listed as Addressed or Unaddressed.
- EPA’s health-based flag identifies violations of contaminant or disinfectant limits or treatment requirements. Monitoring and reporting violations describe required tests or reports. Neither category measures household exposure.
- Addressed means EPA records formal enforcement on a violation that remains unresolved in the snapshot. Unaddressed means no formal action is recorded for an unresolved violation. Resolved can mean compliance was restored, the rule ceased to apply, or further action was unnecessary. Archived is a separate status.
- We count a violation once per water system and group its distinct linked actions. Conflicting records are set aside. Places are EPA-listed search locations and can include mailing locations. Use the provider name and system ID to identify your service.
EPA data dictionary and files · EPA reporting and enforcement FAQ · Find an annual water quality report · How to get the report from your utility