How Much Does It Cost To Build An ADU In Hawaii

Building an ADU in Hawaii is a great way to add value to your home. If you are considering building an accessory dwelling unit (ADU), you need to consider the zoning laws and regulations that apply to your property. If your existing home was built prior to 1976, it may be exempt from certain zoning regulations that apply to new construction. However, if you have a single-family home built after 1976, you must comply with local zoning ordinances.

Building an ADU in Hawaii is a great way to build more housing, add more value to your property, and generate extra income. The state of Hawaii has a number of regulations and policies that make it easy to build an accessory dwelling unit, but there are still some guidelines you need to follow.

Here’s what you need to know:

First, before you get started with any building project, you’ll need a permit from the county department of building safety.

Second, when building an ADU in Hawaii, it’s important that all new structures meet current energy code requirements for energy efficiency. This includes installing insulation in the walls and ceiling, as well as installing ventilation fans and windows with low-E coatings on them so that they let in plenty of natural light while keeping out solar heat gain during warm months but still keeping temperatures cool enough inside during hot ones. It’s also important that these new structures be built using sustainable materials such as bamboo or cedar wood panels instead of plywood or particleboard because they have less impact on the environment than traditional construction materials do, which means they won’t contribute as much greenhouse gas.

How Much Does It Cost To Build An Adu In Hawaii

If you’ve recently bought a lot and would like to build an ADU on it, you’ll want to ask yourself: How much will it cost to build an ADU in Hawaii? This article will give you an idea of what you can expect to pay, the rules that apply, and how to choose a builder.

Building an ADU

Adding an accessory dwelling unit (ADU) is becoming a popular option in Hawaii. These additional structures are typically constructed on the same lot as the main residence and are used for many different purposes. They are ideal for young adults returning home from college or elderly parents seeking additional income. An ADU usually has its own kitchen, bathroom, and bedroom. Building an ADU on your property requires careful planning. Hawaii has specific rules and regulations about this type of development, so make sure you research them before you start.

The first step in building an ADU is to check with your local county and city government officials. Some cities and counties have specific laws about ADUs, and there are several ways to get permits for them. If you live in Honolulu, for example, there are special requirements for an ADU.

Before you begin the construction process, you need to know how much it will cost to build your ADU. It can cost as much as $264,000 to build an 800-square-foot ADU. And depending on your rental rates, it could take up to 10 years before the construction costs are covered. In addition to the cost, you may need to make changes to the landscaping of your home to make it ADU-ready.

An ADU is a great way to add additional income to your existing home. Depending on the location, it can be either a separate structure or a portion of the main house. In Hawaii, an ADU can be as little as 400 square feet, or as large as eight hundred square feet. You can also build an ADU on top of your existing home.


If you’re thinking of building an accessory dwelling unit (ADU) on your Hawaiian island, there are certain rules and regulations that you need to follow. ADUs are additional living spaces that can be added to your single-family lot. They include a full kitchen, bathroom, sleeping space, and at least one parking stall. These units are also known as granny flats or in-law apartments.

DHHL and Hawai’i County are currently reviewing the zoning code for ADUs. According to the county’s planning director, ADU production peaked in 1991, when 581 ADUs were built on the island. However, the production of ADUs has decreased dramatically since then.

ADUs are permitted on lots of up to 3,500 square feet. For lots larger than 5,000 square feet, there are additional requirements. In addition, ADUs must be supported by adequate utilities and include at least one off-street parking space. ADUs are only allowed to be used for long-term rentals and cannot be used for commercial purposes.

Before you start building your ADU, you need to learn the zoning requirements of your property. You can use the DPP’s Property Search to determine the zoning rules in your area. ADUs are not permitted on multi-family units or duplexes. Also, an existing ohana unit cannot be converted into an ADU.


An Accessory Dwelling Unit (ADU) is an additional dwelling unit that is built on a separate piece of property. These units are generally smaller than condos and must have their own separate entry and private parking stall. ADUs are typically rented out by the owners to family members or guests. The cost of an ADU depends on the size of the unit and the connection to the main house.

Before you begin construction, make sure you understand the laws regarding ADUs in Hawaii. They vary from one island to the next, and different residential areas have different rules and regulations regarding them. In addition to zoning and association regulations, there may be homeowner-builder regulations that apply to an ADU. Make sure you research the process of building an ADU and its costs before you begin.

ADUs are a good option for owners who are looking for more income from their homes. The rental income from an ADU can help offset some of the construction costs. Typically, an ADU costs $330 per square foot. For example, an 800-square-foot ADU would cost $264,000 to build. With the permitted rental rates, an ADU can recoup the costs in as little as ten years.

ADUs are a great way to increase the value of a property. In Hawaii, the City and County of Honolulu’s accessory dwelling unit law allow owners to add an extra small dwelling to the property. These units can be attached to a single-family home, or detached from the main house. The extra income can help homeowners pay the mortgage and cover other housing expenses.

Choosing a builder

There are many things to consider when choosing a builder to build an ADU in Hawaii. The most important thing is to choose a builder who is experienced with ADUs. Some are better than others. Depending on your needs, you may need the services of more than one builder.

If you have a lot of space on your property, you may want to consider building an ADU. You can do so with either an attached or detached model. You’ll also have to follow some regulations and codes. In Hawaii, you will need to file a covenant with the Land Court of Hawaii to legally construct the unit.

Another consideration is whether the ADU is permitted on your property. ADUs can only be built on lots that are zoned for residential use and must be at least 3,500 square feet. The property must also have access to a public road. You can apply for an ADU permit online and submit 4 copies of your building plans. You’ll also need to submit a restrictive covenant form.

If you’re building an ADU in Hawaii, you should always hire a contractor who is familiar with this type of construction. It will save you time and money. The right architect and contractor will be able to create a structure that is cost-efficient and energy efficient.

Electrical panel upgrades

Electrical panel upgrades are a common requirement for building an ADU in Hawaii. The primary reason for this is the state’s strict electrical code requirements, which require that the main electrical panel in the house be located within a certain distance of the detached unit. In many cases, this distance requires the main electrical panel to be upgraded to 200-amp service.

In addition to requiring an upgrade to the home’s main electrical panel, electrical permits will often require that you install an additional breaker or circuit breaker in your existing main electrical panel. This can be done by installing a dedicated circuit breaker or adding a sub panel with its own breaker.

The most common way to provide power to an ADU is by installing a separate subpanel containing its own circuit breakers. This method is also what’s used for most commercial buildings and homes that have multiple electric meters (one for each dwelling). If you choose this option, you’ll need to hire an electrician who specializes in installing subpanels.

Sewer capacity

In Hawaii, there is currently a limit on the amount of ADUs a property can have. The number is currently limited to 15,000 per property, but that may increase with time. The city of Honolulu is considering allowing up to 20% of its single-family housing stock to contain ADUs. The city is working with the county to determine areas of the island where existing sewer capacity can serve additional units.

The capacity of a sewer system and water system will vary from location to location. To ensure the capacity of existing infrastructure, prospective applicants should check with the Department of Planning and Permitting. In case the existing infrastructure is not sufficient, no building permit will be issued. The Department of Planning and Permitting has developed a Public Facilities Pre-Check Form for this purpose.

There are a number of reasons to build an ADU on a property. ADUs are a good way to increase rental inventory in Hawaii, and they also allow homeowners to earn additional income. They typically rent for less than a condo unit. Hawaii hopes that ADUs will help to address the housing shortage. If you own land on Oahu and are interested in building an ADU, contact a trusted contractor or the Honolulu Department of Planning and Permitting for more information.

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