Cook County, IL Environmental Rules: Boat Dock Permits (2026)

Cook County's Flood Damage Prevention ordinance, enacted for unincorporated Cook County under Chapter 118, Article III, treats floodway land as the most restrictive flood-hazard tier. " Section 118-43(1) turns that principle into a specific use list: general agriculture, parking lots and public recreation are permitted outright in a floodway, but subsection (1)(b) lists uses "which involve temporary or non-obstructive structures" that "may be permitted upon the issuance of a special use permit," and item 4 of that list names "Marinas, boat rentals, docks piers and wharves" directly, so a private dock, pier, wharf or boat-rental use proposed inside a floodway must clear the county's discretionary special-use process, not a routine building permit.

Section 118-43(1)(c) adds that no structure "shall be erected or maintained or moved within" the floodway, and no fill deposited there, "without a permit issued by the Department of Building and Zoning," and any authorized fill must be offset volume-for-volume by material removed from the floodplain. Applicants who cannot meet the standard have a variance path: Section 118-46(2) allows the Zoning Board to grant relief through "a Cook County Zoning Special Use permit" on a showing of undue hardship, but requires written notice to the applicant that flood-insurance costs will rise and that increased risk of loss is assumed.

Section 118-48 disclaims county liability for flood damage even where a permit is issued. Because Article III applies only within unincorporated Cook County, dock and marina construction inside Chicago or any of the county's 130-plus incorporated suburbs falls under that municipality's own floodplain code, not this ordinance.