Flood Zones: Elmhurst vs Naperville

How high above the base flood elevation must my house be in DuPage County?

Section 15-28 of the Countywide Stormwater and Floodplain Ordinance requires the lowest floor (or lowest entry of usable space) to be at least two feet above the base flood elevation (BFE) shown on the FEMA FIRM. Some municipalities require three feet — check with your local building department.

Where do I find DuPage County flood maps?

The regulatory floodplain follows FEMA Flood Insurance Rate Maps (FIRMs) as adopted by DuPage County. View interactive maps via DuPage County Stormwater Management (dupagecounty.gov/stormwater_management) or FEMA's Map Service Center at msc.fema.gov.

Do I need a permit to build a fence or shed in a DuPage floodplain?

Yes. Any development in the regulatory floodplain — including fences, sheds, fill, grading, or accessory structures — requires a stormwater permit under Chapter 15. Apply through your municipality (if certified) or directly to DuPage County Stormwater Management.

Is Naperville in a flood zone?

Parts of Naperville are in FEMA-designated flood zones along the DuPage River and other waterways. Check your specific property at illinoisfloodmaps.org or the FEMA Map Service Center.

Do I need flood insurance in Naperville?

If your property is in a Special Flood Hazard Area, flood insurance is required for federally backed mortgages. Flood insurance is available for all properties through the NFIP, even outside flood zones.