Floodplains

All new construction (homes, building additions, garages, fences, etc.) in a floodway or floodplain requires a development permit from the Community and Economic Development (CED) department. 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 CED office. You can also contact the CED office at 847-391-5380. If it is unclear whether or not your property is located in a floodway or floodplain, CED 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:

Notes:

1. If in a floodway, development is allowed if in accordance with Title 14 of the City Code. Replacement fences are permitted that do not result in greater obstructions to flood flows. 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.
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 project is an addition and the cumulative improvements total is over 50% the cost of the existing structure, (each improvement % is calculated at the time of each project with an appraisal) the entire structure 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 the foundation to at least 24” above the floodplain 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 along with applying to the Metropolitan Water Reclamation District (MWRD) per the WMO Ordinance.
3. Garages/Gazebos/Decks 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\
4. All permits in the floodplain must have the approval of the PW&E Department.
5. Sheds must be anchored with at least 2 soil anchors on diagonal opposite corners of the shed or with approved equivalent at a 30” depth to secure shed in a flood situation. Also flood resistant materials must be used and permanent openings should be created to allow for flood waters to flow through.
6. Generators are to be placed at an elevation 1' above the 100 year floodplain elevation. The PW&E Department can give you an approximate ground to bottom of generator height. Generators are to be mounted on a foundation separate from the building.

Definitions:

• Floodplain: Land that is subject to inundation by the 100-year frequency flood as identified on the Flood Insurance Rate Map, City of Des Plaines, effective date of August 19, 2008.
• Floodway: That part of the floodplain immediately adjacent to and including the river or creek as identified on the Flood Insurance Rate Map, City of Des Plaines; effective date of August 19, 2008. The floodway needs to be preserved in order to convey and store flood flows.
• Remodeling: Renovating the interior or exterior of an existing structure is permitted (roofing, siding, windows, etc.), however, the aforementioned remodeling must not include expanding the exterior dimensions of the structure.
• Repair: Maintenance or replacement of a patio, driveway, side drive, and walkway are permitted. However, the aforementioned must not include expansion of the original footprint. Any questions relating to maintenance or repair not identified in this brochure should contact the PW&E Department at (847) 391-5390. Maintenance also included items such as foundation repairs, tuck-pointing, replacement plumbing, etc.