What is an Accessory Dwelling Unit (ADU)?
On Oahu, ADUs are defined as secondary residential dwellings which may be permanently installed and rented on residential properties. ADUs can be up to 800 square feet for properties over 5,000 square feet, and up to 400 square feet for properties between 3,500 and 5,000 square feet. ADUs may be fully attached or detached structures, and may include a full kitchen, bathrooms and bedrooms. There is a parking requirement, as well as property set-back rules. CPR properties may not add an ADU in most cases. The City & County of Honolulu offers a free “ADU Pre-Check” to determine if your property is allowed to install an ADU. The Pre-Check is mandatory before getting an ADU build permit.
Many local companies offer ADU design & constructions services, with others offering “kit” models available for the owner to build themselves or to find and hire a General Contractor to build. This website provides a variety of ADU information and resources.
Use this information at your own risk as rules and policies may change. Hawaii ADU LLC assumes no liability for information provided on this site.