Hawaii County, HI Accessory Structures: Tiny Homes (2026)
Tiny home rules in Hawaii County, HI, covering tiny houses on wheels (THOWs), park model RVs, and tiny home on foundation builds, determine where they are legal and how they get permitted.
Key Facts
- Governing code
- HCC § 5B-3-3, Appendix Q
- Max floor area
- 500 sq ft excluding lofts
- Loft limit
- one loft per tiny house
- Min habitable ceiling height
- 6 ft 8 in
- Max fine
- $1,000 per day, petty misdemeanor
Summary
Hawaii County rewrote Appendix Q of the International Residential Code and adopted it into HCC § 5B-3-3, giving tiny houses their own construction rules. A tiny house is capped at 500 square feet of floor area excluding lofts, may hold only one loft, and if it has a loft it can only be used as a detached single-family dwelling, not a duplicate unit or rental annex.
AQ101.1 Scope. This appendix shall be applicable to tiny houses used as single dwelling units and tiny houses that contain a loft. Tiny houses shall comply with the International Residential Code except as otherwise stated in this appendix. AQ101.1.1 Limitations. Tiny houses shall not contain more than one loft, or loft space. Tiny houses that contain a loft may not be used for any purpose other than as a detached single-family dwelling. ... TINY HOUSE. A dwelling which is 500 square feet (37 m2) or less in floor area excluding lofts. The maximum total floor area of 500 square feet shall mean the sum of the horizontal areas of each floor of a building measured from the exterior faces of the exterior walls. The total floor area shall include enclosed attached accessory structures such as garages or storage areas. Unenclosed attached structures such as carports, breezeways, lanais, or porches shall be excluded.
Full Breakdown
Chapter 5B, the residential building code, brings the 2018 International Residential Code onto the Big Island but deletes the model Appendix Q entirely and replaces it with a county version at HCC § 5B-3-3. The 500-square-foot cap counts every floor's horizontal area measured from the exterior wall faces, and it folds in enclosed attached spaces like garages or storage rooms; open lanais, carports, breezeways, and porches don't count toward the limit. 1. 1. 1. Loft rules are their own subsystem: a minimum 35-square-foot floor area, no dimension under 5 feet, a 3-foot minimum ceiling height, and loft access by stairway, ladder, alternating-tread device, or ship's ladder, each with its own width, headroom, and rung-spacing specs under AQ105.
Because Chapter 5B folds into the county's construction code, permitting and inspection for a tiny house run through Chapter 5, the construction administrative code, per HCC § 5B-1-4, the same office that handles building permits island-wide.
Violations & Fines
Building without the required permit or against Appendix Q's specs is a construction code violation under HCC § 5-10-1, covering any structure erected, altered, or occupied in violation of chapter 5B. The county's Public Works enforcement office can serve a written notice of violation on the property owner (and any lessee or tenant) under § 5-10-2, and unresolved violations go to criminal prosecution under § 5-10-3: a petty misdemeanor punishable by up to a $1,000 fine, up to 30 days in jail, or both, with each day of continued violation counted as a separate offense.
Frequently Asked Questions
How big can a tiny house be in Hawaii County?
Can a Big Island tiny house have more than one loft?
Do I need a permit to build a tiny house on the Big Island?
What happens if a tiny house is built without meeting Appendix Q?
Sources & Official References
Other rules in Hawaii County
Compare Hawaii County to another location·View the Hawaii accessory structures overview
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