Overflow and Sewer Grant Program

The Overflow and Sewer Grant (OSG) Program seeks to address local governments' infrastructure needs for Combined Sewer Overflows (CSO), Sanitary Sewer Overflows (SSO), and stormwater management.  

Illinois EPA has $5 million in funding for the OSG Grant Program Notice of Funding Opportunity (NOFO).  There is no maximum or minimum grant award amount.

Eligible activities include CSO Correction, SSO Correction, and/or Stormwater and Subsurface Drainage Water management. Higher priority will be given to projects that reduce the occurrence and severity of CSO and SSO events within eligible municipal entities and increase compliance for eligible municipal entities in regard to NPDES permits and relevant control plans for CSOs and SSOs.  

Specific examples of activities that could be funded through the OSG Program are listed below. The list is not all-inclusive, and inclusion of an activity does not equate to an automatic eligibility for funding under the NOFO. OSG activities include:

1. CSO Correction
   • Installation of separate sanitary and storm sewers
   • Downspout disconnection
   • Overflow tanks/tunnels
   • Infiltration/inflow correctionConveyance infrastructure related to CSO correction
   • Real-time control systems for CSO management
   • Planning and design activity related to an eligible capital project
2. SSO Correction
   • Infiltration/inflow correction
   • Enhancement of collection system, pump station, or treatment facility capacity for the purposes of mitigating SSOs
   • Real-time control systems for SSO management
   • Other capital projects for the purposes of mitigating or preventing the impact of stormwater on wastewater collection
   • Planning and design activity related to an eligible capital project
3. Stormwater and Subsurface Drainage Water
   • Gray infrastructure – conventional piped drainage and water treatment systems designed to move urban stormwater away from the built environment
     • Traditional pipe, storage, and treatment systems
     • Collection and treatment systems for reuse
     • Real-time control systems for CSO management
     • Sediment controls including:
       • Filter fences
       • Storm drain inlet protection
       • Street sweepers
       • Vacuum trucks
     • Planning and design activity related to an eligible capital project
   • Green infrastructure
     • Green roofs, green streets, and green walls
     • Rainwater harvesting collection, storage, management, and distribution systems
     • Real-time control systems for harvested rainwater
     • Infiltration basins
     • Constructed wetlands, including surface and subsurface flow wetlands
     • Bioretention/bioswales (e.g., rain gardens, tree boxes)
     • Permeable pavement
     • Wetland/riparian/shoreline creation, protection, and restoration
     • Establishment/restoration or urban tree canopy
     • Replacement of gran infrastructure with green infrastructure including purchase and demolition costs
     • Planning and design activity related to an eligible capital project.
4. Other
   • Other capital projects for the purposes of mitigating or preventing the impact of stormwater on wastewater collection or treatment.
   • Notification systems that inform the public of combined sewers or sanitary overflows that result in sewage being released into rivers and other waters.

Applicants must apply for a grant through the Grant Accountability and Transparency Act (GATA) Portal, https://grants.illinois.gov/portal/. The OSG Notice of Funding Opportunity (NOFO) was posted May 30, 2025. Applications will be accepted on a rolling basis; those received by the 15th of each month will be reviewed and scored. Applications meeting all eligibility criteria will be reviewed based on the date the application was submitted. Grants will be awarded until all funds are expended or until January 1, 2027, whichever comes first.

Illinois EPA receives the OSG funds through Section 221 of the Clean Water Act and administers the program within Illinois. Per OSG guidelines, rural communities (population 10,000 or less) and/or financially distressed communities (population 30,000 or less and has a median household income (MHI) of 70 percent or less than Illinois’ statewide average) cannot be required to match the program. For non-rural or non-financially distressed communities, the OSG Program may provide up to 80 percent of the approved Project costs. The remainder, 20 percent, is the responsibility of the Grantee and constitutes the match.  The program period is two years unless otherwise approved. This is a reimbursement program.

If you have any questions regarding the program or application, contact:

Illinois Environmental Protection Agency
Bureau of Water
Watershed Management Section
217-782-3362
epa.bowgrants@illinois.gov