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Hamilton County, IN Environmental Rules: Flood Zones (2026)

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

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

Key Facts

Governing map
FEMA FIRM for Hamilton County dated 11/19/2014
Fill in floodplain
Prohibited except narrow ag/park/road uses
Floodway rise limit
0.15 feet maximum increase
State permit needed first
DNR floodway permit under IC 14-28-1
Governing body
Hamilton County Plan Commission / Drainage Board

Summary

Hamilton County's floodplain ordinance covers every special flood hazard area shown on the county's November 19, 2014 FEMA flood insurance rate map and bans filling floodplain land outright, with only narrow exceptions for farming, parks, and public roads approved by the Drainage Board.

These county ordinances apply to unincorporated areas of Hamilton County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

Lands to which this chapter applies. This chapter shall apply to all SFHAs and known flood-prone areas within the jurisdiction of the Hamilton County Plan Commission... Floodplain management. The intent of floodplain management is to protect against loss of property, protect human life, and maintain natural areas that help mitigate flooding. Therefore, filling of land in the floodplain of any unincorporated part of Hamilton County and the drainage shed of any regulated drains is prohibited.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 22 | Unified Development Ordinance: Republication).

Full Breakdown

The floodplain management chapter applies to all special flood hazard areas (SFHAs) and known flood-prone areas within the jurisdiction of the Hamilton County Plan Commission, using the one-percent annual chance flood profiles and flood insurance rate map for Hamilton County dated November 19, 2014, updated by any later FEMA revision. Where FEMA hasn't mapped a watercourse, or the upstream drainage area exceeds a square mile, the Indiana Department of Natural Resources' best available data governs instead. The code treats protecting people and property as the point of the whole scheme: filling land in the floodplain of any unincorporated part of the county, or in the drainage shed of any regulated drain, is prohibited.

The Hamilton County Drainage Board can permit a defined amount of fill only for agricultural uses, forestry and wildlife preserves, county/city/township parks, public streets and bridges, and Surveyor-approved regional detention basins, and only after finding the fill won't meaningfully reduce the floodplain's storage capacity. 15 feet or more, and a state DNR floodway construction permit under IC 14-28-1 must issue before the county's own floodplain development permit can be granted.

Violations & Fines

Building, filling, or altering land in the SFHA without meeting these requirements is punishable by a fine of not less than $10.00 and not more than $2,500.00 per day of violation, treated as a common nuisance under the zoning code. Development that increases the regulatory flood elevation in an identified floodway by 0.15 feet or more is barred outright regardless of permit status, and the state can require the county to submit revised flood data to FEMA under 44 CFR § 65.12 for any channel modification or fill project.

Frequently Asked Questions

How do I know if my lot is in a flood zone?
The county uses the FEMA flood insurance rate map for Hamilton County dated November 19, 2014, plus any later FEMA update, to delineate special flood hazard areas and floodway/fringe boundaries.
Can I fill in a low, wet part of my property?
Generally no. Filling floodplain land in the unincorporated county is prohibited outright, with the Drainage Board only able to approve limited fill for farming, parks, wildlife areas, or public roads.
What's the difference between a floodway and a fringe?
The floodway is the channel and adjoining land that carries the peak flood flow and is the most restricted; the fringe is the rest of the floodplain outside the floodway and allows somewhat more development.
Do I need a state permit before the county will issue mine?
Yes, if your site sits in an identified floodway. The Indiana DNR must issue a permit for construction in a floodway under IC 14-28-1 before the county floodplain administrator can issue the local permit.

Sources & Official References

Other rules in Hamilton County

All Hamilton County rules

Compare Hamilton County to another location·View the Indiana environmental rules overview

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