ADU Permit Requirements
Honolulu, Hawaii
Do You Need a ADU Permit in Honolulu, Hawaii?
Yes, in Honolulu, Hawaii, a building permit is typically required for adu projects. Structures exceeding 800 square feet require a permit, while smaller adus may be exempt. Setback and zoning regulations may still apply even for exempt structures. Always confirm the latest requirements with the Honolulu building department before starting construction.
Permit Status: Yes
Requirements Details
Permit required for structures over 800 sq ft
Maximum height: 16 feet
$1,000-$5,000
Accessory Dwelling Units (ADUs) require building permits in virtually all jurisdictions. Site plan review, utility connections, and compliance with local zoning density requirements are typically required. Some states have streamlined ADU permitting.
Permit Rules for ADUs in Honolulu, Hawaii
In Honolulu, adus exceeding 800 square feet typically require a building permit. Before starting your adu project, it is important to understand the local building codes and permit requirements enforced by the Honolulu building department.
Setback requirements in Honolulu ensure structures maintain proper distances from property lines, typically 5 feet from the front, 5 feet from the sides, and 5 feet from the rear. These regulations help maintain neighborhood aesthetics, ensure safety, and prevent disputes with neighboring properties. Height restrictions also apply, with a typical limit of 16 feet in Honolulu.
Permit fees in Honolulu typically range from $1,000-$5,000 for residential adu projects. The permitting process helps ensure your adu meets structural, safety, and zoning requirements. Building without a required permit can result in fines, required removal, or complications when selling your property.
Always verify current requirements directly with the Honolulu, Hawaii building department before beginning construction.
Example Scenario
If you are planning to build an Accessory Dwelling Unit (ADU) in Honolulu, a building permit is required in virtually all cases. ADUs up to 800 square feet may qualify for streamlined permitting. You will need architectural plans, site plans, and compliance with zoning density requirements. Expect permit fees of $1,000-$5,000, plus impact fees in some jurisdictions. Contact the Honolulu, Hawaii planning department early as ADU regulations are evolving rapidly.
Before You Build: Checklist
- Verify whether your adu project requires a building permit from Honolulu
- Check zoning regulations and setback distances for your property
- Review any HOA or neighborhood covenants that may restrict adu placement, size, or materials
- Confirm your adu meets the 5-foot front, 5-foot side, and 5-foot rear setback distances
- Call 811 before digging to locate underground utilities
- Prepare a site plan showing the adu location on your property
- Budget for permit fees ($1,000-$5,000) and any inspection costs
- Schedule required inspections after construction begins
Where to Apply for a ADU Permit in Honolulu, Hawaii
To apply for a adu building permit in Honolulu, Hawaii, contact the Honolulu Development Services Department or the city's building division. Most municipalities accept permit applications in person at city hall or online through the city's official website. Be prepared to pay permit fees in the range of $1,000-$5,000 and to provide a site plan or project description. Processing times vary, so apply well before your planned construction start date.
Official Resources
Honolulu Official Building and Permit InformationAlways verify requirements directly with official sources before beginning construction.
Frequently Asked Questions
What size adu requires a permit in Honolulu, Hawaii?
In Honolulu, Hawaii, a building permit is typically required for adus that exceed 800 square feet. Structures below this threshold may be exempt from permit requirements, but setback and zoning regulations may still apply. Always verify with the Honolulu building department for the most current rules.
How much does a adu permit cost in Honolulu, Hawaii?
ADU permit fees in Honolulu, Hawaii typically range from $1,000-$5,000. Actual costs may vary based on the scope of your project. Additional fees for plan review or inspections may also apply. Contact the Honolulu building department for current fee schedules.
Can I build a adu without a permit in Honolulu, Hawaii?
Building a adu without a required permit in Honolulu, Hawaii can result in fines, required removal, or complications when selling your home. Structures under 800 square feet may be exempt, but you should verify with the local building department.
Where do I apply for a adu permit in Honolulu, Hawaii?
You can apply for a adu building permit through the Honolulu Development Services Department or the city's building division. Visit the official city website for application forms and submission details. Many cities now offer online permit applications in addition to in-person submissions.
Other Permits in Honolulu
Shed PermitFence PermitDeck PermitPool PermitGarage PermitPergola PermitHot Tub PermitSources
Source: Honolulu Development Services Department
- City Planning Department
- Municipal Building Code
- Official City Website
Last verified: 2026-04-01