Will County, IL Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard required
- 1 foot above BFE (the FPE)
- Governing section
- § 55.062(C)(1)
- Applies to
- regulatory floodplain, countywide
- Garage minimum
- 0.1 ft above BFE
- Civil fine
- $25–$750 per day
Summary
Will County requires new and substantially improved residential structures in the regulatory floodplain to elevate their lowest floor to the Flood Protection Elevation, the base flood elevation plus one foot of freeboard, under the county Stormwater Management Ordinance.
The lowest floor including basements of all new residential structures, substantially improved structures and additions shall be elevated up to at least the FPE. An attached garage for a structure must be elevated up to at least 0.1 feet above the BFE.
(a) If placed on fill, the top of the fill for the residential structure shall be above the FPE. The top of fill for an attached garage shall be at least 0.1 foot above the BFE. The fill shall be placed at that elevation for a distance of ten feet out from the building unless the building design is certified by a registered structural engineer to be protected from damages due to hydrostatic pressures. Additionally, the fill shall not settle below the FPE for the residential structure and not below 0.1 feet above the base flood for an attached garage, and shall be adequately protected against erosion, scour and differential settlement. The fill should not adversely affect surface drainage from or onto neighboring properties.
(b) If elevated by means of walls, pilings or other foundation, the building’s supporting structure must be permanently open to flood waters and not subject to damage by hydrostatic pressures of the base flood. The permanent openings shall be no more than one foot above existing grade, and consist of a minimum of two openings. The openings must have a total net area of not less than one square inch for every one square foot of enclosed area subject to
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2025 S-25: Supplement contains: Local legislation current through Ordinance No. 24-100, passed 4-18-2024 and Res. 23-387, passed 11-16-2023; and State legislation approved through 2024 Pamphlet #2).
Full Breakdown
Under Will County Code § 55.062(C)(1), the lowest floor, including the basement, of every new or substantially improved residential structure, addition, or fill pad within the regulatory floodplain must sit at or above the Flood Protection Elevation (FPE), defined at § 55.005 as the base flood elevation plus one foot of freeboard. Attached garages need only reach 0.1 feet above the BFE itself. The Stormwater Management Ordinance applies countywide, including Joliet, Bolingbrook, Romeoville, Plainfield, and Lockport, unless a municipality becomes a "certified community" enforcing an equally strict ordinance of its own (§ 55.001(C)).
Violations & Fines
Building without meeting the FPE elevation standard violates the county Stormwater Management Ordinance; the Administrator can revoke the permit, issue a stop-work order, and impose a civil fine of $25 to $750 per day under § 55.999.
Frequently Asked Questions
Does Will County require freeboard above the base flood elevation?
Does this rule apply inside Joliet or Bolingbrook?
Sources & Official References
Other rules in Will County
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