Environmental Rules in Bonneville County, ID (2026)
5 rules for unincorporated Bonneville County, Idaho.
Verified from official government sources
Stormwater Management
Bonneville County requires runoff from impervious surfaces to be retained on-site, with lots designed to hold a five-year storm event, or a flat 1.5-inch rainfall for small lots in the Idaho Falls Impact Area.
Bonneville County Drainage & Stormwater Rules
Some RestrictionsBonneville County Code of Ordinances § 156.064
DRAINAGE STANDARDS; DRAINAGE DESIGN AND MAINTENANCE. (A) Runoff from all impervious surface areas on a lot shall be retained on-site. (B) The site shall be designed to retain a minimum of a five-year storm event. Exception: In the Idaho Falls Impact Area on subdivisions of less than one-half acre lot size then a flat one and one-half inch rainfall shall be used.
Erosion Control
Anyone disturbing ground in a Bonneville County right-of-way must get a permit from the County Weed Department first and follow tiered revegetation or erosion-control rules scaled to how much of the ROW is torn up, from a per-foot weed fee up to erosion control blankets.
Bonneville County Right-of-Way Erosion Control Permit
Some RestrictionsBonneville County Code of Ordinances § 91.10
If greater than 30% of the ROW is disturbed, the permittee shall make sure that four inches of top soil exists, or shall import that amount of top spoil necessary to constitute four inches of top soil, and will then reseed the site by means of seed drilling (conventional or no-till) or hydroseeding, or erosion control blankets of the disturbed area utilizing approved grass seed.
Flood Zones
Bonneville County regulates building in areas the Federal Insurance Administrator has mapped as special flood hazard under Chapter 154. Code § 154.07 adopts the county's 2002 Flood Insurance Study and FIRM maps by reference, and § 154.27 requires a floodplain development permit before any development starts in a mapped flood hazard area.
Bonneville County Floodplain Development Permit
Some RestrictionsBonneville County Code of Ordinances § 154.07
§ 154.07 BASIS FOR ESTABLISHING THE AREAS OF SPECIAL FLOOD HAZARD. The special flood hazard areas identified by the Federal Insurance Administrator in a scientific and engineering report titled "Flood Insurance Study (FIS) for Bonneville County, Idaho," dated April 2, 2002 with accompanying flood insurance rate maps (FIRM) or digital flood insurance rate maps (DFIRM), and other supporting da...
Boat Dock Permits
A boat dock counts as regulated development under Bonneville County's floodplain chapter. Building or altering one within a special flood hazard area requires a floodplain development permit, and a dock that encroaches into a mapped floodway faces additional no-rise engineering requirements.
Bonneville County Boat Dock Permit Requirements
Some RestrictionsBonneville County Code of Ordinances §§ 154.27, 154.28(B)(1), 154.49(B)(4)(e)
A floodplain development permit shall be required in conformance with the provisions of this chapter prior to the commencement of any development activities within special flood hazard areas... A complete description of all the development to be permitted under the floodplain development permit (i.e., house, garage, pool, septic, bulkhead, cabana, pole barn, chicken coop, pier, bridge, mining, ...
Flood Elevation Requirements
Bonneville County adds a one-foot safety margin above the base flood elevation for construction in mapped flood hazard areas. Code § 154.02 defines freeboard and fixes it at one foot, and § 154.46 requires new residential construction to elevate its lowest floor no lower than that flood protection elevation.
Bonneville County Flood Elevation Freeboard Rule
Some RestrictionsBonneville County Code of Ordinances § 154.02
FREEBOARD. A factor of safety usually expressed in feet above a flood level for the purposes of floodplain management. FREEBOARD tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, obstructed bridge openings, debris and ice jams, and the hydrologic effec...
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