Floodplain Construction

Floodplain Construction Brochure

New Construction
Remodeling & Repairs

• Floodplain: Land that is subject to inundation by the 100-year frequency flood as identified on the FEMA Map, City of Des Plaines, effective date of November 6, 2000.
• Floodway: That part of the floodplain immediately adjacent to and including the river or creek as identified on the FEMA Map, City of Des Plaines, effective date of November 6, 2000. The floodway needs to be preserved in order to convey and store flood flows.

Step 1: Apply for a permit. All new construction (homes, building additions, garages, fences, etc.), in floodway or floodplain requires a development permit from the Building and Code Enforcement (B&CE) Division (847-391-5380), 3rd Floor of City Hall. Special conditions and building requirements exist for building in these areas. They can be found in Title 14 of the City Code, "Flood Control". Apply for the permit (with your plat of survey) in the B&CE office. If it is unclear whether or not your property is located in a floodway or floodplain, B&CE will send the application to the Engineering Department for a flood zone determination (2-3 days).

Please refer to the following chart to determine if the proposed project is permitted:

1. If in floodway, development is allowed if in accordance with Title 14 of the City code. Fences (chain link) are allowed only if parallel to the flow. Second story additions are allowed if the total accumulated cost of improvements does not exceed 50% of the cost of the existing structure (appraisal required). No foundation expansion is allowed in the floodway. If your house is damaged by an act of God or other cause over 50% of its current market value, then a variation will be required by the City Council to rebuild on this site pursuant to the requirements in Title 14 of the City Code. You will need to hire a professional engineer familiar with the code in order to meet the requirements and secure a permit.

2. If in the floodplain, development is allowed if in accordance with Title 14 of the City code. You will need to hire a professional engineer familiar with Title 14 of the City code. Your engineer will need to prepare a topographic survey and calculations to see if your proposed project can be built.

If the proposed development is over 50% the value of the house (you will be required to provide an appraisal), the entire house will have to be brought into compliance with Title 14 of the City Code (it will be treated like a new house) the requirements of which include, but is not limited to elevating the top of foundation to at least 12" above the flood plain elevation, no basement (existing one would have to be filled in if using the same foundation), and compensatory storage. An elevation certificate from a registered land surveyor is required before occupancy. There are additional requirements for new house construction in the building code.

Sheds/Garages/ Gazebos built on property in the floodplain will need a topographic survey (you will need to hire a registered land surveyor) to determine the existing ground elevations around the structure. The top of the foundation for these structures shall be at least 12" above the floodplain elevation and the foundation shall extend to a depth of 42" below existing grade.

All permits in the floodplain must have the approval of the City Engineering Dept.

Questions regarding the Building Code should be directed to the Building and Code Enforcement Division at 847-391-5380. Questions regarding floodplain and floodway issues should be directed to the Engineering Department at 847-391-5390. The City Code references can be viewed by clicking here.

Guide To Repairs and Remodeling In Flood Hazard Areas

Definitions

Step 1: Apply for a Permit.  All work (repair/remodeling, additions, etc.), in FLOODWAY or FLOODPLAIN requires a development permit from the Building and Code Enforcement Division, 3rd Floor of City Hall. Please note building additions are treated as new construction and the Guide to New Construction in Flood Hazard Areas should be consulted for those requirements.