Kane County, IL Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Governing section
- Kane County Code Sec. 9-139
- Fox River freeboard
- BFE plus 3 feet
- Other floodplains freeboard
- BFE plus 2 feet
- Industrial addition minimum
- BFE plus 1 foot
- Adjacent-to-floodplain cushion
- 0.5 feet above FPE
- Enforcing standard
- Table 9-139.A and 9-139.B
Summary
In unincorporated Kane County, any building in the regulatory floodplain must be elevated or floodproofed to the Flood Protection Elevation (FPE): base flood elevation (BFE) plus a freeboard cushion. Along the Fox River floodplain that cushion runs up to 3 feet above BFE; in other mapped floodplains it is 2 feet, enforced under Code Sec. 9-139.
9-139: BUILDING PROTECTION STANDARDS: This section applies to all buildings located in the regulatory floodplain. However, most new and replacement buildings are not appropriate uses of the regulatory floodway. A summary of the building protection standards is provided in tables 9-139.A and 9-139.B of this section... Notes: 2. An addition to an existing industrial building may be constructed at the BFE plus 1 foot of freeboard as approved by the Administrator. 4. Nonresidential industrial structures may be elevated or dry floodproofed to the FPE. FPE OR FLOOD PROTECTION ELEVATION: The elevation to which a building must be protected from flood damage, through elevation or floodproofing. The FPE is the base flood elevation plus a recommended freeboard.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-17: Code current through: Ord. 26-183, passed 4-14-2026).
Full Breakdown
Kane County Code Sec. 9-139 ("Building Protection Standards") applies to every building sited in the regulatory floodplain mapped from the current FEMA Flood Insurance Rate Map, Flood Insurance Study, or Letter of Map Revision. A, which sets the Flood Protection Elevation, an added freeboard margin above the base flood elevation, that a structure's lowest floor or lowest opening must clear before the Kane County Division of Environmental and Water Resources will sign off on construction. 5-foot freeboard cushion, calculated under the Administrator's review of a soil engineering report.
Non-Fox River floodplains carry a lighter standard: BFE plus 2 feet for structures within the floodplain. Non-residential and industrial structures may instead be dry floodproofed to the FPE rather than elevated, and an addition to an existing industrial building can be built at just BFE plus 1 foot of freeboard if the Administrator approves. 5 feet for smaller overland flow paths under 20 acres, with the Administrator able to require a further 6 inches above normal water level or seasonal high groundwater table. "FPE" is defined at Sec.
the base flood elevation plus a recommended freeboard," while "freeboard" itself is defined as the added height increment covering calculation uncertainty, wave action and debris jams.
Violations & Fines
Building without meeting the FPE triggers a floodplain violation under Chapter 9, defined as failure of a structure or development to comply with the article's floodplain management regulations, including failure to produce a required FEMA Elevation Certificate or other compliance documentation. The Administrator can withhold or revoke a floodplain development permit, and non-conforming structures built below the required elevation fall under the separate non-conforming structures standards of Sec. 9-140, which restrict repair, expansion or substantial improvement until the building is brought up to the current FPE.
Frequently Asked Questions
How much freeboard does Kane County require above base flood elevation?
Can an industrial building floodproof instead of elevating?
What counts as a floodplain violation in Kane County?
Sources & Official References
Other rules in Kane County
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