Hawaii — Code Adoption Summary
Adoption model: Statewide-mandatory floor via the State Building Code Council, but each COUNTY must separately adopt it within 2 years — meaning a real lag/variance window between state adoption and county enforcement is normal. Plus a forward-looking statewide energy mandate (model low-energy/carbon code from 2026-07-01). Last verified: 2026-07-03 Confidence: verified Primary sources: Hawaii State Building Code Council · Hawaii State Energy Office — https://energy.hawaii.gov · ICC HI
Statewide adopted codes — current (2026)
| Code family | Adopted edition | Effective (state) | Source |
|---|---|---|---|
| Building | 2021 IBC | 2022-10-08 | up.codes/hawaii |
| Residential | 2021 IRC | 2022-03-06 | " |
| Electrical (NEC) | NEC 2023 | 2024-09-01 | grassrootinstitute.org |
| Plumbing | UPC 2021 (IAPMO) | 2022-02-26 | " |
| Energy | IECC 2021 | 2023-01-29; counties must adopt through 2026-06-30; from 2026-07-01 must ALSO adopt a state Model Low-Energy & Carbon Code (under development) | energy.hawaii.gov |
Key structural trap: the state adopts a code edition, but each COUNTY has up to 2 years after the state's effective date to formally adopt it — so different Hawaiian counties can legitimately be enforcing different vintages simultaneously. Always confirm the COUNTY's adoption status, not just the state's.
Adoption model & precedence
- State sets the baseline; counties are the actual enforcing AHJ and may lag the state by up to 2 years, or add their own amendments.
- AHJ = county building department (Honolulu, Hawaiʻi, Maui, Kauaʻi each administer separately).
Major cities / counties
| Jurisdiction | County | Notes | Building dept. |
|---|---|---|---|
| Honolulu | City & County of Honolulu | own adoption ordinance/amendments (Art. 1) — confirm current adoption status vs. state | honolulu.gov |
| Hilo | Hawaiʻi County | own amendments — confirm adoption timing | dpw.hawaiicounty.gov |
| Kailua | Maui / Hawaiʻi (name shared — confirm island) | confirm county | respective county dept |
AHJ fallback (when local adoption is unverified)
- State baseline (certain): 2021 IBC/IRC, NEC 2023, UPC 2021, IECC 2021 (energy — with a Model Low-Energy/Carbon Code layer coming 2026-07-01).
- Action: always confirm the specific county's adoption date/status — do not assume county enforcement matches the state's effective date.
Change log
- 2026-07-03 — created; verified NEC 2023 (eff. 2024-09-01), UPC 2021, 2021 IBC/IRC, IECC 2021 + upcoming Model Low-Energy/Carbon Code (2026-07-01); flagged county 2-year adoption-lag structure.