Floodplain Identification

How to Determine if a Parcel is in the Floodplain

Check the effective FEMA Flood Insurance Rate map (FIRM) for your community by visiting FEMA’s website at  The effective FIRM for your community is the only map that determines whether a mortgage lender will require flood insurance for the property. This is also the map that insurance agents use to rate flood insurance policies.

Updates to the FIRM panels are acknowledged by FEMA through Letters of Map Change (LOMC) and include Letters of Map Revision (LOMR) and Letters of Map Amendment (LOMA).  This information can be found on FEMA website where the FIRM panels are located.  Paper copies of all issued LOMCs can also be found in a community’s map repository.

For your convenience, the Countywide FIRM panels with an effective date of August 1, 2019, are also available on the County’s website.

Need Help?

Having difficulty accessing or interpreting the FIRM?  Please contact the community official in the community where the property is located.  For unincorporated properties, contact DuPage County Stormwater at 630-407-6673 or email us at
Request a flood elevation determination for your property by downloading the following form to your computer:

For Real Estate Agents

For more information about floodplains, flood insurance and what you should say to someone looking to buy real estate, check out the following FEMA publications.

Development in the Floodplain

Any applicant wanting to develop a piece of property in DuPage County needs to consult the current effective FEMA Flood Insurance Rate Map (FIRM) to determine if the property is in the floodplain. Please be aware that the FIRM maps do not necessarily identify all areas subject to flooding. Site specific floodplain, depressional storage areas, and local drainage sources of small size are not always represented on the floodplain maps. Actual floodplain boundaries may be slightly different than those shown on the maps due to variations in local topography.

For regulatory information regarding development in a special management area (floodplain) please refer to the DuPage County Countywide Stormwater & Floodplain Ordinance.

For properties in all partial waiver and non-waiver communities, including unincorporated areas, it is recommended that a free pre-application meeting with County staff be scheduled to discuss development plans and the various Stormwater regulations that will be applicable to the site. Please call 630-407-6673 to schedule your pre-application meeting.

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