[§46-4.8] Accessory dwelling units on residentially zoned lots. (a) Each county shall adopt or amend accessory dwelling unit ordinances pursuant to this section to help address deficits in their housing inventory based on Hawaii housing planning studies published by the Hawaii housing finance and development corporation.
(b) Except as provided in subsections (c) and (d), each county shall adopt or amend ordinances defining reasonable standards that allow for the construction of at least two accessory dwelling units, or the reasonable equivalent, for residential use on all residentially zoned lots.
(c) A county that does not adopt or amend an ordinance pursuant to subsection (b) shall adopt or amend ordinances pursuant to this subsection and subsection (d), if applicable, defining:
(d) In addition to the requirements under subsection (c), a county with a population of five hundred thousand or more shall adopt or amend an ordinance defining reasonable standards to add development potential in existing apartment districts or apartment mixed-use districts equivalent to the county's projected five-year demand of needed housing units for ownership or rental in the 2019 Hawaii housing planning study.
(e) Accessory dwelling units developed pursuant to this section shall be subject to all development standards adopted by the respective county, including but not limited to those adopted pursuant to this chapter.
(f) Nothing in this section shall preclude a county from denying applications for permits if there is insufficient utility infrastructure to service the additional demand caused by the development of accessory dwelling units pursuant to this section.
(g) If a county does not adopt or amend zoning ordinances pursuant to this section by December 31, 2026, the county shall not deny any permit application on the basis of exceeding the maximum number of housing units allowed if any owner, or their designated representative, of a single-family dwelling in a residentially zoned lot applies for construction of up to two accessory dwelling units, or the reasonable equivalent, until the county adopts or amends an ordinance pursuant to this section; provided that a county may deny a permit application on the basis of infrastructure, design, or development standards.
(h) No county shall adopt prohibitions on using any dwelling unit on a residentially zoned lot as separately leased long-term rentals, as defined by each county.
(i) This section shall not apply to:
(j) Neither this section, any permit issued in accordance with this section, or structures developed pursuant to this section shall create any vested rights for any applicant, permit holder, or land owner. This section shall not preempt a county's ability to accept, review, approve, and deny permit applications.
(k) For purposes of this section, "residentially zoned lot" means a zoning lot in a county zoning district that is principally reserved for single-family and two-family detached dwellings. "Residentially zoned lot" does not include a lot in a county zoning district that is intended for rural, low density residential development, and open space preservation. [L 2024, c 39, §1]