HI · State directory
Hawaii ADU rules
Official accessory dwelling unit regulations for 4 jurisdictions in Hawaii, plus statewide law.
Not sure which county yet?
We have read the ordinances for 4 Hawaii counties and lined them up side by side: detached vs internal, size limits, owner occupancy, and approval process.
Statewide ADU law
Hawaii has state-level ADU legislation that applies across local jurisdictions. Local rules below may add requirements on top of state law.
- capitol.hawaii.govOfficial sourceVerified August 2026https://www.capitol.hawaii.gov/hrscurrent/Vol02_Ch0046-0115/HRS0046/HRS_0046-0004_0008.htm
- data.capitol.hawaii.govOfficial sourceVerified August 2026SLH2024 Act39 (PDF)https://data.capitol.hawaii.gov/sessions/sessionlaws/Years/SLH2024/SLH2024_Act39.pdf
- capitol.hawaii.govOfficial sourceVerified August 2026https://www.capitol.hawaii.gov/hrscurrent/Vol04_Ch0201-0257/HRS0205/HRS_0205-0020.htm
- capitol.hawaii.govOfficial sourceVerified August 2026https://www.capitol.hawaii.gov/hrscurrent/Vol02_Ch0046-0115/HRS0046/HRS_0046-0004.htm
Counties & regions
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