Building permits in Honolulu County, Hawaii
Find the right authority before you build. Honolulu County permitting follows Hawaii law — here is exactly who issues the permit and where to start.
County issues permits
City and County of Honolulu — Dept. of Planning & Permitting (DPP)
Hawaii has no incorporated municipalities. On Oahu the City and County of Honolulu Dept. of Planning & Permitting (DPP) is the sole building-permit authority for the entire county, issuing building, electrical, mechanical, and plumbing permits.
Open the official permit portal →
Permits, plan review, and inspections are handled through the Honolulu Internet Permit System (HIPS) and the DPP permit centers in Honolulu and Kapolei.
Permit cheat-sheet (Hawaii rules)
| Project | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | Permit required | county | Valuation-based; set by the county building department (R-3 / U occupancy schedule). | Plan review typically several weeks; varies by county workload. | Generally allowed | Hawaii’s statewide ADU law (Act 50, 2008) allows one accessory dwelling unit per single-family lot; the four counties administer permits and set local size/setback rules. Owner-occupancy and parking standards vary by county. Exempt: Statewide ADU law allows one ADU per single-family lot; counties set size limits (commonly 400–1,000 sq ft by county). |
| 🪵 Deck / Porch | Conditional | county | Valuation-based; set by the county building department. | Plan review for permitted decks; over-the-counter for simple low platforms where exempt. | Generally allowed | All structural lumber above ground must be preservative-treated for Formosan termite resistance per Hawaii’s amended code; wind-load design (105–170 mph gusts by location) applies. Verify with the county building department. Exempt: Platforms, walks, and driveways not more than 30 in above grade and not over a basement are exempt. |
| 🧱 Fence / Wall | Conditional | county | Permit fee set by county; many low fences are exempt from a building permit. | Exempt fences need no permit; over-height fences go through plan review. | Generally allowed | Vegetation-clearing, shoreline setback, and Special Management Area (SMA) review can add requirements even for exempt fences. Verify with the county. Exempt: Honolulu & Hawaii County: fences/walls over 6 ft require a permit; Maui allows up to 7 ft before a permit. Walls over 30 in (Honolulu) need a permit. |
| 🛖 Shed / Outbuilding | Conditional | county | Valuation-based; Hawaii County charges $10 per 100 sq ft for U-occupancy accessory structures. | Exempt sheds need no permit; permitted sheds go through plan review. | Generally allowed | Agricultural buildings may be exempt under HRS §46-88 (up to 1,000 sq ft nonresidential). Verify with the county building department. Exempt: One-story detached accessory buildings (storage sheds, tool sheds, playhouses) ≤120 sq ft are exempt in all four counties. |
| 🪜 Basement Finish | Permit required | county | Valuation-based; includes trade permits. | Standard plan review where basements are constructed. | Generally allowed | Basements are uncommon in Hawaii, but the same permitting logic applies when one is built or finished. Verify with the county building department. Exempt: Cosmetic finishing (paint, flooring) is exempt. |
| 🚗 Garage / Carport | Permit required | county | Valuation-based; includes trade permits. | New-structure plan review; varies by county. | Generally allowed | Attached and detached garages require a full building permit and plan review. Verify with the county building department. Exempt: New detached structures over 120 sq ft require a permit (smaller are still subject to zoning). |
| ☀️ Rooftop Solar PV | Permit required | county | Building + electrical permits; fee set by county. | Counties offer expedited/solar-specific review for standard rooftop PV. | Generally allowed | Provide racking structural design for tile or flat-roof installations; meet hurricane/wind uplift requirements. Verify with the county building department. Exempt: No size exemption; large/ground-mounted systems need structural review. |
| 🌡️ HVAC Replacement | Conditional | county | Mechanical permit; fee set by county (Maui lists Motors & HVAC trade permits). | Trade permits often issued same-day or over-the-counter. | Generally allowed | Equipment must meet current energy-efficiency and mechanical code requirements. Verify with the county building department. Exempt: In-kind replacement in the same location may be exempt; verify with the county. |
| 🍳 Kitchen Remodel | Conditional | county | Valuation-based when structural/plumbing/electrical work is included. | Standard review for permitted scopes. | Generally allowed | Hawaii’s energy code is reviewed on remodels (insulation, window U-factor, HVAC). Verify with the county building department. Exempt: Cabinet/countertop swap in the same layout is exempt. |
| 🛁 Bathroom Remodel | Conditional | county | Valuation-based when plumbing is relocated. | Standard review for permitted scopes. | Generally allowed | Ventilation to the exterior is required. Verify with the county building department. Exempt: Fixture-for-fixture swap in place is often exempt. |
| 🏗️ Room Addition | Permit required | county | Valuation-based; includes trade permits. | County plan review; multiple inspections. | Generally allowed | Lot-coverage, shoreline/SMA, and energy-code compliance are reviewed. Verify with the county building department. Exempt: No exemption — any new conditioned footprint requires a permit. |
| 🪟 Window / Door Replacement | Conditional | county | Usually no fee for in-kind swap; permit needed if opening is enlarged. | In-kind swaps typically need no review. | Generally allowed | Replacement products should meet energy-code U-factor when the code is triggered. Verify with the county building department. Exempt: Same-size, in-kind replacement is generally exempt. |
| 🏘️ Roof Replacement | Conditional | county | Often exempt/over-the-counter for same-footprint re-roof; fee set by county if required. | Same-material re-roof is typically exempt or over-the-counter. | Generally allowed | Counties list re-roofing with same/similar material for R-3/U occupancies as exempt. Verify with the county building department. Exempt: Same-material, same-slope re-roof often exempt. |
| 🅿️ Driveway / Parking Pad | Conditional | county | Building permit often not required; curb-cut/right-of-way work is separate. | Right-of-way permits reviewed by the county. | Generally allowed | A separate right-of-way permit is usually needed to cut the curb or connect to the street. Verify with the county. Exempt: Platforms, walks, and driveways not more than 30 in above grade are exempt. |
| 🏊 Swimming Pool / Spa | Permit required | county | Valuation-based; includes barrier/fencing and electrical bonding review. | Plan review; barrier inspection required before filling. | Generally allowed | Hawaii follows the IRC barrier requirements (4 ft minimum, no climbable openings). Verify with the county building department. Exempt: In-ground, >3 ft deep, or >5,000 gal pools always require a permit; above-ground prefab <24 in deep (or <5,000 gal, Maui) may be exempt. |
| 🧱 Retaining Wall | Conditional | county | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in hillside/SMA zones have stricter rules. Verify with the county building department. Exempt: Walls with ≤3 ft of retained earth and ≤6 ft total height (not supporting a surcharge or impounding liquids) are exempt. |
| 💥 Demolition / Teardown | Permit required | county | Demolition permit fee set by the issuing authority; verify locally. | — | Generally allowed | A full teardown or major strip-out requires a demolition (building) permit. Demolition permits commonly require proof of utility disconnects (water, gas, electric, sewer) and may require asbestos/lead-paint clearance for pre-1978 homes before work begins. Verify the issuing authority for your specific property. |
| 🚰 Septic System | Permit required | state | Septic permit fee set by the state environmental/health authority; engineered systems cost more. | — | Generally allowed | New or replacement onsite wastewater (septic) systems require a permit from the Hawaii Department of Health Wastewater Branch. A soil/perc evaluation and engineered design are typically required; licensed installers perform the work and the system is inspected before backfill. |
| 🔌 EV Charger | Conditional | county | Electrical permit; fee set by the issuing authority. | — | Generally allowed | A home EV charging station (240V branch circuit + wall-mounted EVSE) requires an electrical permit and must meet the NEC (Article 625). Many jurisdictions fast-track residential EVSE. A load calculation and possible service upgrade are reviewed. |
| ⚡ Standby Generator | Conditional | county | Mechanical/electrical permit; fee set by the issuing authority. | — | Generally allowed | A permanently installed standby generator requires mechanical and electrical permits (transfer switch, fuel gas/propane line). Setback, carbon-monoxide ventilation, and noise rules apply; some HOAs restrict generator placement. |
Frequently asked questions
Who issues building permits in Honolulu County, Hawaii?
City and County of Honolulu — Dept. of Planning & Permitting (DPP) is the permitting authority for Honolulu County. The county issues permits for both unincorporated areas and incorporated cities. Start at the official portal linked above.
Do I go to the county or my city for a building permit in Honolulu County?
The county issues permits for both unincorporated areas and incorporated cities.
What home projects need a permit in Honolulu County?
The same project types shown in the cheat-sheet above (ADU, deck, fence, shed, solar, and more) — rules follow Hawaii state law. Whether the county or your city issues it depends on your property's incorporation status.
How do I apply for a permit in Honolulu County?
Use the official permit portal linked above. Most offices accept online submissions; have your plans, site information, and contractor details ready before applying.
Sources: City and County of Honolulu — Dept. of Planning & Permitting · City and County of Honolulu — Dept. of Planning & Permitting (Building Permits FAQ) · Hawaii County — Building Permits (Dept. of Public Works) · Maui County — Permits, Applications & Fee Schedule · Kauai County — Building Division Permitting