Floodplain Development - Development Services

(Please see https://adacounty.id.gov/developmentservices for the latest version of this information)

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Floodplain Development

What is a floodplain?

A floodplain is an area adjacent to a river, creek, lake, stream or other waterways that is subject to flooding when there is a significant run-off event.

The technical definition of a floodplain as it pertains to the development process can be found in Ada County Ordinance 835.

Boise River
Floodplain management is an important aspect of public health and safety

What do I need to know if my property is in a floodplain?

  • Any development within the Floodplain will require a Floodplain Development Permit.

If you are considering development within a Floodplain, please view the entire Flood Hazard Overlay District Ordinance. The floodplain Submittal Checklist along with a Master Application includes everything you need to submit an application. Please feel free to contact the Ada County Engineer at (208) 287-7925 with any questions you may have.

Where can I get more information:

Development Services 
Ada County Courthouse
200 W. Front St., Boise, ID 83702
Phone: (208) 287-7900, FAX (208) 287-7909