Kankakee County, IL Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard requirement
- 1 foot above base flood elevation
- Fill-method floor height
- 1 foot above FPE, plus 10-ft fill apron
- Manufactured homes
- Elevated 1 foot above FPE, tied down
- Critical facilities
- 500-yr elevation or +3 ft over 100-yr, greater
- Fine for violation
- $100.00 to $750.00 per day
Summary
In unincorporated Kankakee County, any new building in the mapped floodplain must be protected below the flood protection elevation (FPE), which the code defines as the base flood elevation plus one foot of freeboard. Section 109-81 sets the trigger points and lets builders comply by elevating on fill, on open foundations, or, for nonresidential buildings, through certified dry floodproofing.
FPE or flood protection elevation means the elevation of the base flood plus one foot of freeboard at any given location in the floodplain. ... In addition to the damage prevention requirements of section 109-80, all buildings to be located in the floodplain shall be protected from flood damage below the FPE. ... The lowest floor (including basement) shall be one foot above the flood protection elevation;
Full Breakdown
00 in value, is a substantial improvement (over 50 percent of market value or a 20 percent floor-area increase within ten years), repairs substantial damage, or is a manufactured home or a travel trailer sited more than 180 days. Builders can comply three ways. On permanent fill, the lowest floor including the basement must sit one foot above the FPE, with fill placed in one-foot lifts and extended at least ten feet beyond the foundation. On open foundations such as piers, stilts or crawlspace walls, the lowest floor, and all mechanical, electrical and plumbing equipment, must sit at or above the FPE, and enclosed areas below it need at least one square inch of flood-vent opening per square foot of enclosed area.
Nonresidential buildings may instead be dry-floodproofed watertight below the FPE if a registered professional engineer certifies the design. Manufactured homes and travel trailers set for permanent installation must be elevated one foot above the FPE and tied down under the Illinois Mobile Home Tie-Down Act, 77 Ill. Adm. Code § 870. New or substantially improved critical facilities, such as fire and police stations, get an even higher standard: the 500-year flood elevation or three feet above the 100-year elevation, whichever is greater.
Violations & Fines
Building below the required flood protection elevation without a permit, or without meeting § 109-81's standards, is a violation of § 109-24. The planning director gives written notice, and if it is not corrected in ten days, the county can seek a circuit court injunction and the offender is fined $100.00 to $750.00 per offense, with each day counted as a separate violation, plus a recorded judgment against the property's title.
Frequently Asked Questions
How much freeboard does Kankakee County require above the base flood elevation?
How do I meet the flood protection elevation if I build on fill?
Can a commercial building be floodproofed instead of elevated?
Sources & Official References
Other rules in Kankakee County
Compare Kankakee County to another location·View the Illinois environmental rules overview
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