ADU Models and Resources from HPM Hawaii
As the cost of living in Hawaiʻi continues to rise, Accessory Dwelling Units (ADUs) have become a practical response to the state's housing challenges. HPM Hawaii offers a range of ADU models available throughout the islands, covering everything from initial design to project completion. Their offerings are intended to support both the broader housing shortage and the multigenerational living arrangements that are a common part of island culture.
Because each county in Hawaiʻi operates under its own set of ADU regulations, HPM Hawaii has compiled resources covering all counties. This helps property owners evaluate whether their lot qualifies for an ADU and understand what the process involves before committing to a project.
ADU Model Options
HPM Hawaii offers a selection of floor plans suited to a range of needs and lot sizes. Several of these models carry pre-approved status on Hawaiʻi Island, which can help streamline the permitting process. All models are available for purchase statewide, regardless of pre-approval status. The available models include:
- Kehalani – An efficiency dwelling of 416 sq. ft., 0 bed / 1 bath. Pre-approved for low-wind zones.
- Li'ili'i – A studio layout at 480 sq. ft., 0 bed / 1 bath. Pre-approved for low-wind zones.
- Pilikai – A 685 sq. ft. cottage-style unit, 1 bed / 1 bath. Pre-approved for both high- and low-wind zones.
- Anuhea – A compact 528 sq. ft. unit, 1 bed / 1 bath. Pre-approved for low-wind zones.
- Kainani – A 722 sq. ft. model, 1 bed / 1 bath. Pre-approved for low-wind zones.
- ʻAuliʻi – A 1,392 sq. ft. unit, 2 bed / 2 bath. Pre-approved for high- and low-wind zones.
- 'Olu'olu – A 940 sq. ft. model suited for ohana or additional dwelling use, 2 bed / 1 bath. Pre-approved for low-wind zones.
- Huaka – A 1,632 sq. ft. unit, 3 bed / 2 bath. Pre-approved for high- and low-wind zones.
- Keola – An open-concept 1,672 sq. ft. design, 3 bed / 2 bath. Pre-approved for low-wind zones.
Non-pre-approved models are also available and allow for some modifications to better fit a specific property or lifestyle. All designs are intended to comply with applicable state and county guidelines.
Navigating ADU Requirements in Hawaiʻi
Planning an accessory dwelling unit in Hawaiʻi involves more than selecting a floor plan. Requirements differ significantly by county and can include minimum lot sizes, maximum allowable square footage, parking provisions, water and sewer considerations, setbacks, open yard requirements, clearances between structures, and separate entrance specifications. These factors can vary not only by county but also by individual property conditions.
As of September 2024, ADU regulations across Hawaiʻi remain subject to change. HPM Hawaii recommends verifying current requirements directly with the relevant county planning department before proceeding.
HPM Hawaii's Home Planning Consultants work with clients through site assessment, model selection, permitting, and construction. Their role includes helping property owners understand what is feasible on a specific lot and navigating the regulatory requirements that apply to their location. Whether the goal is to create a granny flat, an in-law suite, a backyard cottage, or a detached accessory dwelling unit for rental income, HPM Hawaii provides guidance through each stage of the process.
For county-specific ADU regulations, HPM Hawaii directs property owners to the official planning departments of Hawaiʻi County, Honolulu County, Maui County, and Kauaʻi County.