East Honolulu, HI Accessory Structures: Garage Conversions (2026)

East Honolulu is governed by the City and County of Honolulu Land Use Ordinance (ROH Chapter 21). The LUO allows an existing, legally established accessory structure (such as a detached garage) constructed in the country or residential district to be converted into an accessory dwelling unit. Under the conversion-of-accessory-structures provision, the Director of the Department of Planning and Permitting may allow the converted unit to exceed the ADU maximum floor area, or be exempted from the additional off-street parking requirement, only after finding that viable constraints do not allow reducing the floor area of the existing structure and that no feasible alternative off-street parking site exists due to the placement of the structure on, or the topography of, the zoning lot.

An ADU may be created by converting a legally established structure (attached or detached), an attic, or a basement, but the conversion must still meet all other development standards for the underlying district and the single-ADU-per-lot limit. 140-1(a), a one-car or two-car carport or garage that was allowed to encroach into a required front or side yard "shall not be converted to or be used for a use other than a carport or garage," so a yard-encroaching garage cannot be turned into living space. An owner of a structure built without a permit before September 14, 2015 (the ADU ordinance effective date) who wants to convert it to an ADU must obtain an after-the-fact building permit and bring the structure into conformance.