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Metropolitan Water Reclamation District of Greater Chicago

Excessive infiltration and inflow (I/I) into the sanitary sewer system is a serious problem that contributes to sanitary sewer overflows (SSOs) and basement backups (BBs). The Environmental Protection Agency (EPA) and the Illinois EPA (IEPA) imposed special conditions in the National Pollutant Discharge Elimination System (NPDES) permits issued for the MWRD’s Water Reclamation Plants (WRPs) that requires tributary local separate sanitary sewer satellite entities to implement measures in addition to those required under the 1985 Sewer Summit Agreement if excessive I/I in the system causes or contributes to SSOs or BBs. Due to this mandate, the MWRD incorporated an updated Infiltration and Inflow Control Program (IICP) that was developed with the help of an Advisory Technical Panel (ATP) into the Watershed Management Ordinance (WMO).

Watershed Management Ordinance Article 8: Infiltration/Inflow Control Program  (118 KB)

The MWRD has developed a Technical Guidance Manual (TGM) to provide satellite entities assistance on the IICP requirements and compliance.

TGM Article 8: Infiltration/Inflow Control Program

TGM additional IICP Information

The MWRD distributes annual status reports on the Infiltration / Inflow Control Program.

November 2023 Annual Status Report on the Infiltration / Inflow Control Program, Volume 8

I/I Information Pamphlet for Homeowners

Annual Reporting Forms and SSO and BB Internal Summary Form

IICP Reporting Forms

Email the completed Annual Summary Report to

Previous I/I workshop and meetings:

IICP Training Workshop

If you have any questions about the Infiltration/Inflow Control Program, contact Ms. Ann Gray at