ADU Pass
Honolulu
Honolulu County portion
Also in: No County
ADU Pass helps homeowners in Honolulu, Honolulu County, Hawaii navigate the permit paperwork for building an accessory dwelling unit. This area covers 13 ZIP codes.
Map
ADU details
ADU legality: allowed-with-restrictions
Hawaii partially preempts local ADU restrictions; cities retain authority over design and setbacks. Honolulu permits ADUs subject to local conditions per its zoning ordinance.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 150 | $3,500 | $97,500 | $101,000 |
| 600 | 600 | $3,500 | $390,000 | $393,500 |
| midpoint | 575 | $3,500 | $373,750 | $377,250 |
| maximum | 1,000 | $3,500 | $650,000 | $653,500 |
Fee breakdown
Viability (permitted uses)
- Long-term rental: yes Long-term rental of ADU generally permitted; landlord-tenant law and any city rental-registration ordinance apply.
- Short-term rental: with-restrictions STR rules vary by city. Honolulu regulates STRs separately from ADU permitting; check local STR ordinance and HOA covenants.
- Office rental: with-restrictions Detached office rental requires home occupation permit or rezoning.
- Home office: yes Home occupation permitted with restrictions on signage and customer traffic.
- Studio / workshop: yes Personal artist studio is a permitted accessory use.
- Agriculture: with-restrictions Limited urban agriculture permitted in residential zones; livestock varies by district.
- Relative support: yes Family-occupancy ADU explicitly permitted in single-family zones.
Utilities
- Water: Honolulu Water Utility · 30d connect · $4,500
- Sewer: Honolulu Sewer / Wastewater · 30d connect · $5,500
- Electric: Honolulu Electric Utility · 21d connect · $1,800
- Gas: Honolulu Gas Utility · 30d connect · $1,500
Property values & taxes
Construction timeline
Realistic total: best 7mo · typical 11mo · worst 16mo
Financing
State ADU loans:
Insurance impact
HOA prevalence & preemption
Hawaii SB 3202 (2024) prohibits private covenants recorded after the effective date of the act from limiting the number of ADUs on residentially-zoned urban-district lots below the state floor of two ADUs per lot, and from restricting long-term rental of ADUs. Critically, the prohibition applies only to NEW covenants; covenants recorded BEFORE the effective date are grandfathered and remain enforceable. Hawaii planned-community associations are governed generally by HRS § 421J (Planned Community Associations Act, applies to associations existing as of 1997-06-16), and condominiums by HRS § 514B. Neither chapter contains a broader ADU-specific preemption beyond the SB 3202 forward-looking limitation. Owners subject to a recorded HOA declaration that pre-dates SB 3202 and prohibits or restricts ADUs have no state-law ADU remedy against that declaration.
Regulatory overlays (2)
- flood-zone
Honolulu has FEMA Special Flood Hazard Areas; elevation certificates and flood-resistant construction required for SFHA parcels. - historic-district
Honolulu historic districts trigger Architectural Review Board / Historic Preservation Commission review for ADUs in historic boundaries.
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
- Amendment
Legal history (timeline)
Current ordinance: City of Honolulu Municipal Code — Accessory Dwelling Units, adopted 2020-01-01, last amended 2024-04-01
- 2024-01-01 — City of Honolulu ADU code refresh (city-ordinance)
Conforming local-code amendments aligning with current Hawaii accessory-dwelling framework.
Effect: Codified permissive ADU standards consistent with state law and local zoning.
City and County of Honolulu — county ADU rules and overlays
County ADU ordinance
The City and County of Honolulu is a unified consolidated city-county under Hawaii Const. Article VIII and the Honolulu City Charter (~1,000,000 residents — Hawaii's only consolidated city-county; covers the entire island of Oahu plus the Northwestern Hawaiian Islands; the state capital and Hawaii's largest jurisdiction). There is no 'unincorporated Honolulu County' — every parcel on Oahu lies within the consolidated city-county and is governed by the Land Use Ordinance (LUO, Revised Ordinances of Honolulu Chapter 21), administered by the Honolulu Department of Planning and Permitting (DPP). Hawaii enacted SB 3202 (Act 39, 2024) creating the 'Ohana Zoning Reform Act, requiring all Hawaii counties to permit at least one accessory dwelling unit (ADU) by-right on residentially-zoned parcels meeting basic infrastructure tests. Honolulu's pre-existing 'Ohana Dwelling Unit (ODU) regulations under LUO § 21-3.110-3 already permitted accessory dwellings on most R-3.5, R-5, R-7.5, R-10, and R-20 parcels with a ohana use permit; Honolulu City Council adopted Ordinance 24-03 in 2024 to align local rules with Act 39 and adopted Bill 7 (2024) creating an additional accessory dwelling unit (ADU) classification distinct from ohana that allows separate rental.
County regulatory overlays
Hawaii state — ADU law and programs
State ADU law
Hawaii enacted statewide ADU preemption through SB 3202 SD2 HD3 CD1 (2024 Regular Session), signed by Governor Josh Green in 2024. The act requires each of Hawaii's four counties (Honolulu, Hawaii, Maui, Kauai) to adopt or amend ordinances by 2026-12-31 permitting at least two accessory dwelling units (in addition to the primary unit) on every residentially-zoned lot within the urban district. Counties retain authority to set conditions on where and under what circumstances the additional ADUs can be built (placement, size, design, parking, infrastructure adequacy). The act also prohibits private covenants recorded after the effective date from limiting the number of ADUs below the state floor or restricting long-term rental of ADUs; covenants recorded before the effective date are grandfathered (see stateHoaPreemption). The 2024 session also passed companion measures addressing condominium and association governance.
State HOA preemption
Hawaii SB 3202 (2024) prohibits private covenants recorded after the effective date of the act from limiting the number of ADUs on residentially-zoned urban-district lots below the state floor of two ADUs per lot, and from restricting long-term rental of ADUs. Critically, the prohibition applies only to NEW covenants; covenants recorded BEFORE the effective date are grandfathered and remain enforceable. Hawaii planned-community associations are governed generally by HRS § 421J (Planned Community Associations Act, applies to associations existing as of 1997-06-16), and condominiums by HRS § 514B. Neither chapter contains a broader ADU-specific preemption beyond the SB 3202 forward-looking limitation. Owners subject to a recorded HOA declaration that pre-dates SB 3202 and prohibits or restricts ADUs have no state-law ADU remedy against that declaration.
State financing programs
Hawaii does not operate an ADU-specific statewide loan, grant, or forgivable-loan program. The Hawaii Housing Finance and Development Corporation (HHFDC), within the Department of Business, Economic Development, and Tourism (DBEDT), administers the state's affordable-housing finance and development programs: the Hale Kamaaina Mortgage Loan (first-time homebuyer mortgage for Hawaii residents), Down Payment Assistance and Single-Family Mortgage programs, Low-Income Housing Tax Credit (LIHTC) allocation, Hula Mae Multi-Family revenue bonds, and rental housing programs. None target ADU construction directly; an ADU-bearing primary residence on Hawaii's urban-district lots can qualify for the underlying mortgage when other criteria are met. Implementation of SB 3202 may bring ADU-specific products in 2026-2027 but none has been announced as of 2026-04-26.
State housing programs
Hawaii's state-level ADU programs operate primarily through the SB 3202 preemption framework with implementation due 2026-12-31. The state does not yet maintain a statewide pre-approved ADU plan catalog. The Honolulu County (City and County of Honolulu) Department of Planning and Permitting maintains an established ohana-dwelling permitting framework that pre-dates SB 3202 and serves as a working model for the other three counties' implementation. The Hawaii ADU manual published by Hawaii ADU (advocacy organization) at https://hawaiiadu.org/ is widely used as a homeowner-side reference but is not a state program. No statewide ADU impact-fee waiver statute exists.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.
ZIP Codes
- 96813
- 96814
- 96815
- 96816
- 96817
- 96818
- 96819
- 96820
- 96821
- 96822
- 96825
- 96826
- 96850
Post Office
- 1111 Lunalilo St, 96822
- 1271 N King St, 96817
- 330 Saratoga Rd, 96815
- 335 Merchant St Fl Ground, 96813
- 3600 Aolele St Rm 208c, 96820
- 4354 Pahoa Ave, 96816
- 7040 Hawaii Kai Dr, 96825
- 91 Sand Island Access Rd, 96819