Honolulu, HI Accessory Structures: Carport Rules (2026)

Carports on Oahu are governed jointly by Chapter 21 of the Revised Ordinances of Honolulu (the Land Use Ordinance, or LUO) and Chapter 16 (the Building Code). In every residential district (R-3.5, R-5, R-7.5, R-10, R-20, AG-1, AG-2, P-1, P-2, and Country District), a carport that is attached to the dwelling or is detached but located within the buildable envelope follows the same setbacks as the principal residence: typically a 10-foot front yard, 5-foot side yards, and 5-foot rear yards in the R-5 district, with larger setbacks in lower-density residential and country districts. Where an existing dwelling makes those setbacks impossible, the homeowner can apply for a Zoning Adjustment under LUO §21-2.140-1 (Specific circumstances). The DPP's January 29, 2025 Zoning Adjustment instructions for Carports and Garages require all of the following: (1) no other viable alternative site exists relative to the location of an existing dwelling (including additions) legally constructed prior to October 22, 1986, and/or relative to the topography of the zoning lot; (2) the landowner authenticates the nonconformity of the existing dwelling, carport, or garage if necessary; and (3) the maximum horizontal dimensions of the carport or garage do not exceed 20 feet by 20 feet, except where dimensions can be reasonably increased to accommodate an existing retaining wall or similar condition. Any carport approved through this adjustment process cannot later be converted into a habitable or storage room. The application fee is $600 ($200 review fee plus $400 processing), doubled if the work was already done without approval ('after-the-fact' applications also require a licensed land surveyor's certified site plan). DPP must process the application within 45 days of acceptance, and an unprocessed application is deemed approved. Independent of the adjustment, every carport regardless of location requires a building permit under ROH Chapter 16 and must be designed to the wind-load (Hawaii Building Code Appendix W) and seismic provisions that apply to Oahu; a steel post-and-beam carport on a concrete slab is the most common compliant design. Carports, garages, and unsupported lanais do not count toward the floor area ratio (FAR) used to size dwellings under LUO §21-3.70-1, which is why carport conversions back to enclosed garages or living space typically require a separate permit and may push the lot over its FAR cap. Under the parking standards in LUO Article 6, a single-family dwelling on Oahu must have at least two off-street parking stalls, which the carport can satisfy. Driveways onto public streets require a separate sidewalk/driveway permit from the city's Department of Facility Maintenance. Country District and Special District carports (Diamond Head, Hawaii Capital, Punchbowl, Waikiki, North Shore, Haleiwa, Thomas Square/Honolulu Academy of Arts) face additional design review under the relevant special-district guidelines, and any carport in a Special Management Area (SMA) along the shoreline triggers SMA review under HRS Chapter 205A and ROH Chapter 25.