A new Maui County law allows two accessory dwelling units on every residential-zoned lot throughout the county, as long as the property has access to fire, water, wastewater and related infrastructure.
Mayor Richard Bissen signed Bill 78 (2026) into law July 8, only a day after the Maui County Council unanimously approved it, making Maui the last county in the state to comply with a 2024 state law that requires all the counties to allow two ADUs per lot by the end of 2026.
The Grassroot Institute of Hawaii supported the measure as a means to reform Maui’s convoluted ADU regulations.
Homeowners on Lanai, for example, could only build ADUs on lots larger than 7,500 square feet. But almost 75% of the island’s residential lots are smaller than that, which made ADUs effectively illegal there.
Meanwhile, on Molokai, where most residential lots are 10,000 square feet or larger, homeowners were limited to building just one unit. On Maui, however, homeowners could build two ADUs on lots larger than 7,500 square feet, but smaller lots were limited to just one.
Jonathan Helton, a policy analyst with Grassroot, explained in testimony that the bill could help make housing more affordable.
“Allowing more homes on the same lot is an approach many states and cities across the county have used to increase housing supply,” he said. “Research indicates these changes have helped moderate or reduce housing prices.”
In earlier hearings, members of the Council expressed similar hopes.
Councilmember Gabe Johnson of Lanai said the island’s small homes might make it easier for owners to use the new ADU provisions. “I think there’s room for us to have that really work well,” he told the Housing and Land Use Committee on June 3.
Lanai, Maui and Molokai homeowners interested in building ADUs under these rules are encouraged to speak with the planning and water supply departments before applying for permits to make sure their lots have access to adequate infrastructure.
