Honolulu, HI Accessory Structures: ADU Permits (2026)

Honolulu's LUO (Chapter 21, Revised Ordinances of Honolulu) creates two parallel accessory unit programs. The Ohana Dwelling Unit under LUO Sec. 21-5.700 has been allowed since the 1980s on lots in residential districts (R-3.5 through R-20) that meet minimum lot area, generally 7,500 sq ft for R-5 with potential for a second kitchen within the principal dwelling envelope. The ADU under LUO Sec. 21-5.730 (created by Bill 7, 2015) allows a separate accessory dwelling on lots of at least 3,500 sq ft in R-5, R-7.5, R-10, and R-20 districts, subject to infrastructure capacity confirmation by Board of Water Supply, Department of Facility Maintenance (sewer), and DPP. ADU maximum is 800 sq ft on lots up to 5,000 sq ft and 1,000 sq ft on larger lots. Setbacks follow underlying district standards. All ADU/Ohana permits require building, electrical, and plumbing permits through DPP's Honolulu ePlans system. Properties in Special Management Area (SMA) coastal zones need separate SMA approval. The Bill 7 ADU program is conditioned on a 5-year recorded covenant restricting use to long-term rental (180+ day leases).