Hawaii ADU Laws & Rules (2026)

Compare ADU zoning rules across 1 Hawaii cities. Average ADU score: 7.0/10.

Avg Score: 7.0/101 Cities

Key Hawaii ADU Laws

Hawaii ADU Overview

  • 1 cities currently covered with detailed ADU zoning data
  • Average ADU-friendliness score: 7.0/10
  • Rules vary by city — check individual city pages for details
  • We're actively expanding coverage in Hawaii

Hawaii Cities ADU Comparison

CityMax SizeSetbacksPermit FeesBuild Cost1BR RentScore
Honolulu 500 sq ft (lots under 5,000 sq ft); 1,000 sq ft (lots 5,000 sq ft and larger) — updated by Ordinance 25-2 Standard building code requirements $3,000-$8,000 estimated (higher utilities/inspection costs) $150,000-$300,000 $1,600-$2,200 7/10

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