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Brown County, WI Environmental Rules: Flood Zones (2026)

Heavy Restrictions

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

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

Key Facts

Ordinance: Brown County Ch. 23
FIRM Effective: May 9, 2023
Districts: FW, FF, GFP
State Code: Wis. Stat. §87.30 / NR 116

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 Brown County, WI.

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 Brown County, WI on the FEMA flood map

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

Summary

Brown County Code Chapter 23 (Floodplains), revised 02-15-2023, regulates development in unincorporated areas under Wis. Stat. §87.30 and FEMA NFIP. Three districts: Floodway (FW), Floodfringe (FF), and General Floodplain (GFP). Updated FEMA Flood Insurance Rate Maps took effect May 9, 2023.

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

23.05 AREAS TO BE REGULATED. (1) This ordinance regulates all areas of special flood hazard identified as zones A, AO, AH, A1-30, AE, VE, V1-30, or V on the Flood Insurance Rate Map (FIRM). Additional areas identified on maps approved by the Department of Natural Resources (DNR) and unincorporated areas of Brown County may also be regulated under the provisions of this ordinance, where applicable. (2) Any structures intended for human habitation adjacent to a floodplain that the Zoning Administrator deems susceptible to flooding must have the lowest opening a minimum of two feet above the area of special flood hazard, regional or base flood elevation. A shoreland permit will be required. If elevations do not exist, it may be required to complete a case by case flood study or to record an affidavit for unmapped floodplain onto the deed of the property.

Source: City of BrowncountyView official code

Full Breakdown

Chapter 23 implements Wisconsin's mandatory floodplain zoning under Wis. Stat. §87.30 and Wis. Admin. Code NR 116. The Floodway District prohibits structures intended for human occupancy and most fill. The Floodfringe District allows development with the lowest floor elevated to or above the Flood Protection Elevation (typically 2 feet of freeboard above the Base Flood Elevation per Wis. Admin. Code NR 116.13). The General Floodplain District requires hydraulic/hydrologic studies before development. Major flood-prone areas in Brown County include the Fox River corridor, East River, Duck Creek, and the Bay of Green Bay shoreline. Floodplain development permits are required from Brown County Planning and Land Services for unincorporated parcels; incorporated cities (Green Bay, De Pere, etc.) administer their own floodplain ordinances.

Violations & Fines

Violations of Wis. Stat. §87.30 and NR 116 enforced through county zoning citations; non-conforming work can require removal. Federal NFIP non-compliance can jeopardize community flood insurance eligibility.

Frequently Asked Questions

Do I need a permit to build in a Brown County flood zone?

Yes. Any development in the Floodway, Floodfringe, or General Floodplain districts requires a floodplain development permit from the local zoning authority. Brown County in unincorporated areas, or the municipality elsewhere.

Sources & Official References

Other rules in Brown County

Noise Ordinances: Construction HoursSome Restrictions Flood Elevation RequirementsSome Restrictions Erosion ControlSome Restrictions Stormwater ManagementSome Restrictions Noise Ordinances: Aircraft NoiseSignificant Restrictions Noise Ordinances: Barking DogsFew Restrictions Noise Ordinances: Amplified Music & Outdoor SoundSome Restrictions Noise Ordinances: Decibel LimitsSome Restrictions Noise Ordinances: Vehicle NoiseFew Restrictions

All Brown County rules

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Flood Zones in Cities Across Brown County

Ashwaubenon, WI De Pere, WI Green Bay, WI