Everyone in Hawaii heard the headline: the state now requires counties to allow two accessory dwelling units on residential lots. Almost nobody heard the three sentences that follow it in the statute.
In this segment I go through what Act 39 actually reaches — and what it quietly leaves out.
What this covers:
- Act 39, which began as Senate Bill 3202 and took effect 28 May 2024, and the 31 December 2026 deadline it puts on every county
- Why the mandate stops at the boundary of the state urban district
- The two carve-outs written into the law: special management areas, and any area a county deems at high risk of flooding, lava or fire
- The provision that surprises people most — Act 39 does not touch private covenants recorded before 28 May 2024, so an older subdivision’s CC&Rs can still ban an ADU outright
- Why a county can still turn you down on utility infrastructure grounds even where the mandate applies
UPDATE, September 2026: this segment was recorded earlier in the year, and the counties have since begun acting. Honolulu adopted Ordinance 25-2, with its ADU and ʻohana provisions effective 30 September 2025. Maui County adopted expanded accessory dwelling rules on 17 July 2026, so qualifying residentially zoned properties there may now be eligible for up to two accessory dwellings alongside a primary residence. The state-law analysis in this video stands; the county picture is further along than it was when I recorded. Current as of September 2026.
Who this is for: Oʻahu and neighbour-island homeowners wondering whether the yard is worth more built than mowed. Owners in older subdivisions who should check their CC&Rs before they call an architect. Mainland and overseas buyers weighing a Hawaii purchase where a second unit carries part of the holding cost. Families trying to keep the next generation on-island.
Four things to confirm about your own parcel before you spend a dollar on drawings: whether it sits inside the state urban district, whether it falls in a special management area, whether your county maps it as high natural hazard, and what your recorded covenants say. Any one of them can end the project.
Nothing here is legal advice. Before breaking ground or marketing an ADU, talk to a licensed architect, your county building department, and a real estate attorney.
If you want to know what a permitted second unit is worth to a buyer — or whether your lot can carry one — I am happy to look at the parcel with you.
Jason Wong (PB), MBA — President & Principal Broker
Island Dragonfly LLC · Oʻahu, Maui, Big Island, Kauaʻi, Molokaʻi, Lānaʻi
License RB-22819 · Firm RB-24348
Serving clients in English and Chinese
Personal site: https://jasonwong.us
Brokerage: https://islanddragonfly.com
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