ADU Journal  /  Rules by State  /  Idaho
Rules by State / Idaho

Idaho ID ADU Rules

Last updated: April 2025 ยท Reviewed by ADU Journal editorial team
ADU Friendliness Score
30
โ˜… Restrictive
Permitting Ease 28
Size Allowances 32
Financing Access 30
Local Flexibility 25

Size & Dimensions

Max ADU Size (Detached) Determined locally
Max ADU Size (Attached) Determined locally
Min ADU Size Determined locally
JADU Max Size Not recognized statewide
Max Height (Detached) Determined locally
Stories Allowed Determined locally

Setbacks & Lot Coverage

Rear Setback Determined locally
Side Setback Determined locally
Front Setback Determined locally
Minimum Lot Size Determined locally
Fire Sprinklers Determined locally

Owner Occupancy & Rental Rules

Owner Occupancy Required? Locally Regulated
Short-Term Rental (Airbnb) Determined locally
Rental Income Allowed? Yes
ADUs Per Lot Determined locally
No statewide standard

Permitting Process

Review Timeline (Ministerial) Determined locally
Permit Fees Determined locally
Design Review Required? Determined locally
Preapproved Plans Available? No statewide program