The A to Z of ADUs (Accessory Dwelling Unit)

ADU Builders CA

ADUs or Accessory Dwelling Units are separate living units that consist of a bedroom, bathroom, kitchen, and living area. ADUs can be built on a property that has a main residential building existing on it. While building an Accessory dwelling unit, you need to obtain necessary permits for the same; failing which you cannot build an ADU on your property. If you want to build an ADU on your property by a professional ADU contractor, then you can contact ADU Builders in your location. Our experts will help you build your dream ADU without creating any hassles. Moreover, we will help you obtain all the necessary permits so that you do not face any legal issues later. So, let us know about the types of ADUs, the permits you need to build an ADU, and the rules of building an ADU that apply to your location.

Garage conversion ADU

If you do not use your garage very often then you can convert this space into an ADU, which will also save a lot of garden space on your property. You can clear the space by removing everything in your garage into a storage unit and making space for building an ADU unit there. This type of ADU is suitable for areas where the density of the population is high. In such areas, there is a shortage of housing and hence limited space is available on your property. So, if you want to build an ADU on your property with limited space, then you can go with this option. You can build a garage conversion ADU in both attached and detached garages.

Basement ADU

You can also convert your basement into an ADU without adding too much to the space. In this type of ADU, you do not need to build anything as you have to only convert your basement into an attractive living room. You can add windows and doors to this unit to make it complete. You can also add shelves and furniture to make the space look amazing. However, you need to abide by the ADU ordinance and build a separate entrance to make it a legal ADU. The space should not be attached to the main house with a door and it should function as a completely separate unit.

Attached ADU

The attached ADU is a separate section but is still connected to your main house. However, you have to build a separate entrance for this unit so that it can fulfill the legal requirements of an ADU. This unit is also known as the addition ADU and helps to generate more space in your house. You can use this space as your home office and other work-related usages. If your parents are staying with you then it can be an ideal place for them. They can stay here comfortably without compromising their privacy.

Detached ADU

Detached ADU is a separate house built on your property and is detached from the main residential unit. This house is eligible for one bedroom, one kitchen unit, and one bathroom. This place can be an ideal home for your parents where they can stay comfortably with all amenities available. Moreover, you can rent this place to tenants for some extra income if there are no elder members in your family. You can build an ADU with a maximum of 1200 square feet of area. However, you have to abide by the ADU rules and regulations so that it won’t create any hassle in the future. If your property is really big hen you can build this type of ADU to generate more space for your house. Your caretakers can also live there without any hassles.

Rules to follow while building an ADU on your property

  • The ADU unit should be built on the same property and a single main residence should be there on that property. The ADU should not be a part of any property that belongs to someone else other than the owner of the main residence.
  • The ADU unit must be attached or detached from the primary residential unit. However, it should not be a standalone building structure. Hence, you can build a 2nd legal unit by obtaining approval from your local planning department.
  • The owner or tenant who has a lease agreement for at least one/two years must be living in the ADU unit. Moreover, you have to live in both units simultaneously to call it a legal second unit.
  • The ADU unit should provide utility and a lot of space to the primary residence. It must consist of an independent kitchen, bathroom, and bedroom even if the space is not adequate. The ADU unit cannot work only as a storage unit, an occasional guest room, or an office unit.
  • The ADU unit should be built on the minimum square footage of 100 square feet and a maximum of 1200 square feet. You should build a separate entrance for your ADU unit.


You have to obtain permits from HOA (if it applies to your locality), County, and Public Works Department. However, obtain the permits earlier so that it does not take too much time and delay the construction process.

If you want a parking area then you can get help from both your local planning department and the HOA. They will permit you for the same if there is any such provision available on your property. Building a parking area also depends on the size of your property. You can hire a professional contractor who will help you build your ADU unit.


Besides these, you have to follow the zoning restrictions and environmental restrictions while building an ADU on your property. While converting your garage into an ADU, you need to understand the building codes. If you are confused about the same, you can take the help of a professional who can guide you with all the necessary information.