Idaho ADU Laws

Complete 2026 guide to accessory dwelling unit regulations

◐Moderate State Law

📋Quick Facts

Owner Occupancy
May be required
Parking
Set locally
Approval Process
Varies locally
Effective Date
7/1/2023

📜Recent Legislation

H0166 (2023) - Prohibits certain restrictions on internal ADUs, signed into law effective July 1, 2023

⚠️Key Requirements & Restrictions

  • •Only covers internal ADUs (within existing structures)
  • •Prohibits restrictive covenants that ban internal ADUs on single-family properties
  • •Does not mandate local government allowance - only restricts HOA/covenant powers
  • •Boise allows detached ADUs up to 2 bedrooms, Ada County limits to 1 bedroom

📖Detailed Analysis

Moderate statewide law H0166 (2023) effective July 1, 2023 - focuses narrowly on prohibiting restrictive covenants from banning internal ADUs within existing single-family dwellings. Does not mandate local government approval or address detached ADUs. Cities retain full local control over zoning/permitting. Boise allows both attached and detached ADUs with up to 2 bedrooms, design consistency required. Ada County permits only 1 bedroom ADUs. Idaho represents limited state intervention - protects internal conversion rights from HOAs but doesn't create comprehensive ADU framework like CA/WA/OR. Most restrictive of Western ADU laws.

🔗Official Resources

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⚠️ Disclaimer

The information provided on this website is for general informational purposes only and does not constitute legal, financial, or professional advice. ADU laws, regulations, and requirements vary by jurisdiction and change frequently. While we strive to keep this information accurate and up-to-date, we make no representations or warranties of any kind about the completeness, accuracy, reliability, or suitability of this information. Always consult with qualified local professionals, including attorneys, architects, and your local planning department, before making any decisions regarding ADU construction or investment. Use of this information is at your own risk.

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Last updated: February 2026