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Kane County, IL Environmental Rules: Flood Zones (2026)

Significant Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

FEMA flood zone rules in Kane County, IL, also called floodplain regulations or special flood hazard area (SFHA) rules, determine flood insurance requirements and elevation standards for new construction.

Key Facts

Floodplain map source: Current FEMA FIRM/FIS/LOMR
Design flood standard: 1% annual chance (BFE)
Large-drainage study threshold: 640+ acres upstream
Floodway building restriction: Sections 9-142, 9-143 apply
Civil fine: $25-$750 per day
State permit: IDNR-OWR needed on Fox River

FEMA Flood Zone Lookup

FEMA assigns every parcel in the U.S. a flood-hazard designation on its Flood Insurance Rate Maps (FIRMs). Zones starting with A or V are high-risk Special Flood Hazard Areas where federally backed mortgages require NFIP flood insurance. Zone X indicates moderate-to-minimal risk, where insurance is optional but often recommended. Your specific zone determines insurance cost, build elevation, and permit requirements in Kane County, IL.

Zone	What it means	NFIP required?
A	High-risk flood area; 1% annual chance flood, no detailed analysis.	Yes
AE	High-risk; same as A but with established Base Flood Elevations.	Yes
AH	High-risk shallow flooding (1-3 ft), usually ponding.	Yes
AO	High-risk shallow flooding (1-3 ft) with sheet flow on sloping terrain.	Yes
V	High-risk coastal zone subject to wave action (no BFE).	Yes
VE	High-risk coastal zone with wave action and established BFEs.	Yes
X (shaded)	Moderate risk; between the 1% and 0.2% annual chance flood.	Recommended
X	Minimal risk; outside the 0.2% annual chance floodplain.	No

Look up Kane County, IL on the FEMA flood map

FEMA maps update periodically; verify zone before buying flood insurance or building.

Summary

Any development inside the FEMA-mapped regulatory floodplain of unincorporated Kane County falls under the county's stormwater management ordinance. The base flood elevation is fixed from the current Flood Insurance Study, and any part of a site sitting inside the regulatory floodway above that elevation is held to the tougher floodway standards until FEMA issues a map revision.

City-specific rules exist: Aurora, and Elgin have their own flood zones rules that differ from Kane County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

The BFE shall be delineated on the site topography to establish the regulatory floodplain area limits for regulation under this chapter. Regulatory floodplains shall be delineated on the site map from the current FEMA FIRM, FIS or LOMR and include those areas of the SFHA which are not regulatory floodplains. The current version of the maps adopted and published by FEMA for regulation under the NFIP together with any amendments, additions, revisions or substitutions thereto or therefor adopted and published by FEMA at any time in the future are hereby referred to, adopted, and made part hereof as if fully set out in this chapter.

View official code

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 Chapter 9, the Stormwater Management Ordinance adopted by Ordinance 19-151 on May 7, 2019, delineates the regulatory floodplain from the current FEMA Flood Insurance Rate Map, Flood Insurance Study or Letter of Map Revision under section 9-136(A). The base flood elevation, the one-percent annual chance flood profile, sets the regulatory line; where no BFE exists and the upstream drainage area reaches six hundred forty acres, a professional engineer must run a site-specific study using models such as HEC-RAS or HEC-HMS and submit it to the Illinois Department of Natural Resources Office of Water Resources (IDNR-OWR) under section 9-136(B). If a parcel sits inside the mapped regulatory floodway at an elevation above the BFE, section 9-136(C) subjects that ground to the floodway standards of sections 9-142 and 9-143, including restrictions on new structures, until a Letter of Map Amendment or Revision is issued.

Section 9-137's general performance standards forbid any development that would raise flood stage or velocity on- or off-site, require new construction to be anchored against flotation and built with flood-resistant materials, and require a Conditional Letter of Map Revision from FEMA before building where a project would change the floodplain or BFE. Fox River projects need a separate IDNR-OWR permit. A stormwater management permit from the county is required before any of this work begins under section 9-28, and violations carry a civil fine under section 9-288.

Violations & Fines

Developing in the regulatory floodplain without the required stormwater management permit, or violating the floodway or performance standards, exposes the responsible party to a civil fine of $25 to $750 per day under section 9-288, with each day of continued violation a separate offense. The Administrator or Director can also revoke the permit, issue a stop-work order, and require the site restored to its pre-development condition.

Frequently Asked Questions

What triggers Kane County's floodplain rules on a piece of property?

Any parcel that falls inside the current FEMA-mapped regulatory floodplain, or that touches a wetland, is subject to Chapter 9 of the Kane County Code. The base flood elevation from the current Flood Insurance Study sets the regulatory boundary under section 9-136(A).

Can I build in the floodway if my lot sits above the base flood elevation?

Only if the structure meets the floodway standards in sections 9-142 and 9-143, which limit new construction largely to accessory structures and bridges that will not block flood flows, until FEMA issues a map revision confirming the ground is out of the floodway, per section 9-136(C).

Who enforces Kane County's floodplain standards?

The Administrator and Director of the county's stormwater program enforce Chapter 9. They can fine a violator $25 to $750 per day, revoke a stormwater management permit, issue a stop-work order, or require the site restored to its prior condition under section 9-288.

Does the Fox River need a separate permit?

Yes. Section 9-137(D) requires any development along the Fox River to also obtain a permit from the Illinois Department of Natural Resources Office of Water Resources in addition to the county's stormwater management permit.

Sources & Official References

[1]Kane County Code § 9-136 (Kane County, Illinois Code Library)

Other rules in Kane County

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All Kane County rules

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