Accessory Structures in Canyon County, ID (2026)
4 rules for unincorporated Canyon County, Idaho.
Verified from official government sources
ADU Impact Fees
Unincorporated Canyon County, Idaho charges a $1,581 development impact fee per accessory dwelling unit built inside the Canyon Highway District No. 4 Mid-Star Service Area. The fee funds road improvements, not the ADU permit itself, and applies only outside Caldwell, Nampa and the county's other incorporated cities.
ADU Road Impact Fee, Unincorporated Canyon County
Some RestrictionsCanyon County Code § 11-04-09
11-04-09: CHD4 MID-STAR SERVICE AREA DEVELOPMENT IMPACT FEE: ... (2) The Impact Fee costs per service unit for the Canyon Highway District No. 4 Mid-Star Service Area are as follows: ... Land Use Category Cost per Unit Units ITE Code ... Single Family Housing $5,050 per dwelling unit 210 ... Accessory Dwelling Unit $1,581 per ...
ADU Owner Occupancy
Canyon County Code § 07-14-25 requires the owner of the lot to live on site wherever a secondary residence, the county's version of an accessory dwelling, is built in unincorporated Canyon County, Idaho. The secondary unit must also carry its own street address for emergency responders.
Canyon County Secondary Residence Owner Rule
Some RestrictionsCanyon County Code § 07-14-25
(1) The owner of the lot or parcel containing the secondary residence must live on site. (2) The secondary residence must have its own address and address numbers shall be placed on the home for emergency purposes.
Shed & Carport Rules
Unincorporated Canyon County, Idaho treats a shed as an 'accessory structure,' defined in Canyon County Code § 07-02-03 as subordinate and incidental to the main building on the parcel. Height is capped by zone under § 07-10-21(3): 35 feet in the Agricultural and Residential Zones, 50 feet in Commercial Zones, and 75 feet in Industrial Zones, and a Development Services Department building permit is required regardless of zone.
Canyon County Shed Height & Permit Rule
Some RestrictionsCanyon County Code §§ 07-02-03, 07-10-21(3)
ACCESSORY STRUCTURE (BUILDING): A structure which is subordinate, and incidental, to the principal structure or use pertinent to the same parcel. ... Commercial Zones C-1, Not applicable 50' 50' C-2, MU-A Industrial Zones M- Not applicable 75' 75' 1 and M-2
Tiny Homes
Unincorporated Canyon County builds tiny homes under Appendix R of the 2018 International Residential Code, adopted at Canyon County Code § 06-01-11. A tiny home still needs the same building permit, contractor registration and inspections as any other residential structure.
Canyon County Tiny Home Building Code
Some RestrictionsCanyon County Code §§ 06-01-11, 06-01-17
(2) International Residential Code for One- and Two-Family Dwellings, 2018 edition, to also include: ... Appendix ... R, “Tiny Homes”. ... It shall be a misdemeanor for any person to fail to comply with any of the provisions of this article which shall be punishable as provided for in Idaho Code 18-113, as amended, in the Magistrate Division of the District Court of the 3rd Judicial District of...
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