Lake County, IL Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard above BFE
- 2 feet (Flood Protection Elevation)
- Substantial improvement minimum
- 1 foot above BFE
- Attached garage minimum
- 0.5 foot above BFE
- Applies to
- Unincorporated Lake County only
- Enforced by
- Planning, Building and Development Dept.
Summary
New homes in unincorporated Lake County floodplains must have their lowest floor built up to the Flood Protection Elevation: base flood elevation plus two feet of freeboard.
(2) Building protection requirements for residential structures shall follow applicable FEMA regulations and include the following: (a) The lowest floor including basements of all new residential structures, including additions, shall be elevated up to at least the Flood Protection Elevation (FPE). The floor of an attached garage for a new structure must be elevated up to at least one-half of one foot above the base flood elevation (BFE).
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-15: Supplement contains: Local legislation current through Ord. 26-0618, passed 6-9-2026 | State legislation current through ILCS Pamphlet 2025 #5).
Full Breakdown
Under the county's Unified Development Ordinance, the lowest floor (including basement) of every new residential structure built in the regulatory floodplain of unincorporated Lake County must sit at or above the Flood Protection Elevation, defined as the base flood elevation plus two feet of freeboard. Attached garages need only reach one-half foot above base flood elevation. Substantially improved existing homes must reach at least one foot above base flood elevation. Compliance is verified through FEMA elevation certificates submitted with the site development permit. This applies only to unincorporated county land. Waukegan, Highland Park, Gurnee, Libertyville and other municipalities administer their own floodplain ordinances.
Violations & Fines
Building below the required elevation without a Planning, Building and Development Director-approved permit is a code violation subject to stop-work orders, permit denial, and the county's general floodplain enforcement remedies under Chapter 151.
Frequently Asked Questions
How much freeboard does Lake County require above base flood elevation?
Does this apply inside Waukegan or Highland Park?
Sources & Official References
Other rules in Lake County
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