What is an ADU? Everything You Need to Know About Accessory Dwelling Units

With California in the midst of a housing crisis, the State has taken several steps to encourage the creation of housing through the passage of several bills such as California Senate Bill 1069 and Assembly Bill 2299.  More specifically, these bills allow property owners to build Accessory Dwelling Units, also known as ADUs. Here is everything you need to know about ADUs.

Frequently Asked Questions

What is an ADU (Accessory Dwelling Unit)?

ADU stands for Accessory Dwelling Unit, which is a second or additional home behind the primary structure on a single parcel.

ADUs can be built on the same lot as single family homes, apartment buildings, and several other residential structures. A garage that is converted into livable space (with all proper building and safety permits) is also considered an Accessory Dwelling Unit.

Where are Accessory Dwelling Units allowed?

The State’s bills allow ADUs to be built anywhere in the state, regardless of what the local municipal code says.

There may be several local ordinances that also govern ADUs (for example: setback requirements stating how close to the property line you can build), but individual cities CANNOT prevent you from creating an ADU, so long as the parcel meets the State’s standards.

What are the different types of Accessory Dwelling Units?

There are 3 primary types of ADUs:

  1. Site built: Traditional construction where a contractor brings the building materials to the site and constructs the dwelling from the ground up.
  2. Manufactured: Built in a factory off-site, transported to the site, and installed on a foundation that was prepared prior to the arrival of the manufactured ADU.
  3. Garage-conversion: An existing structure that is converted to a livable space with all the necessary building and safety permits that have been issued by the local governing agency.

What are the benefits of building an ADU?

The primary benefit is providing housing to an individual or family who needs it. The property owner will reap the financial benefits in the form of rental income.

Adding an ADU to a property allows an owner the option to keep an elderly parent nearby and in close sight. The additional dwelling offers the potential to have a college student live at home without having to live under the same roof as their parents.

Is a manufactured home permitted as an ADU?

Yes, a manufactured home is permitted.​

Can I sell or rent my ADU?

You can definitely rent the ADU. You can only sell an ADU along with the other primary structures on the parcel (for example: the existing single family home) but you cannot sell the Accessory Dwelling Unit individually. 

Manufactured ADUs

Why choose a manufactured ADU over a site built ADU?

With this approach, there is a controlled cost: you pay a single price for a completely finished dwelling. There is a definitive delivery time, which is not always the case with traditional construction.

In about 30 days, the ADU can be ordered from the manufacturer and installed on the foundation.

What is the process for manufactured ADU?

The first step is to pull permits with the City of Long Beach or local governing agency. This is done by submitting building plans for reviewal.

Once the permits have been received, the home is ordered from the manufacturer.

Within 30 days, the foundation, electrical, sewer connection, plumbing, etc. has been completed and is ready to for the ADU to be set on top. In a 60-day period, the permits should have been granted, the house has been ordered and delivered, and tenants placed.

Is a manufactured home built to the same standard as a regular home?

The simple answer is yes. The home must be manufacturer well, as it travels down the freeway at 55 miles per hour and must stay intact. The finishes are selected at the time the order is placed, allowing various customizable options including floorplan, cabinets, countertops, and more.

Being the same or better quality as a traditionally built home, this approach allows for a much easier install, as the home comes fully equipped with all the necessary systems.

Manufactured dwellings are considered HUD-labeled homes, which are built to federal standards that supersede local building and safety codes. This means that the building methods cannot be challenged by the state, county, or city.

Will the market give you the same rental income?

A manufactured home should achieve the same rents as any other dwelling. Being that it is brand new construction, this will appeal to prospective renters.

How much does it cost to get a manufactured ADU?

In most cases, manufactured ADUs cost around $100 per foot. (For example, a 600 square foot ADU will cost around $60,000). This accounts for approximately half of the total cost.

There are other associated costs, such as school and library bonds, fire department fees, sewer connections fees. For a 1-bedroom, 1 bath the total cost will be around $150,000 and for a 2-bedroom, 2 bath the total cost will be around $175,000.

What will adding an ADU do to the value of my property?

There is much debate surrounding ADU valuation. The rental income generated by the accessory dwelling unit will dictate how much value the ADU will add. This can be determined by finding the market rental rate for similar properties in the same area.

Site Built ADU

How long does it take before I can start building?

 In most cases, the plans can be developed and submitted to the City within 1-2 months. For a new build or conversion, you will need to have architectural plans, structural plans, and Title 24.

For all plans to be created and approved, this will take approximately 3 months and then construction can begin.

Is the city of Long Beach making it easy to build an ADU?

Because State law supersedes local laws, this has put pressure on cities to allow faster permitting processes. Many cities have adopted a pro-ADU approach and are now also encouraging property owners to create housing.

How long does it take to build an ADU?

The most common size at the moment is around 500 square feet and is currently taking between 3-4 months to complete. Garage conversions take between 2-3 months.

What is easier: building from the ground up or converting a garage?

A garage conversion is the easiest method of creating an ADU. The typical garage is used as storage by many property owners, so it makes the most sense to change the use and make the structure a livable space.

When converting a garage, many of the local requirements, such as property line setbacks, are eliminated, making the permit process easier. If your property is located within a half mile of public transit, the city cannot require you to add parking.

How long does a garage conversion take?

A typical garage conversion takes approximately 2 months.

Which is more popular right now: a garage conversion or an ADU build?

Both types of ADUs are in high demand.

What is the cost of building an ADU?

When calculating the cost of the finished product, it is typically around $250 per square foot. A garage conversion will cost approximately $200 per foot. These price per foot values factor in all plans, permits, fees, materials, and labor. The price per foot will change depending on the finishes and amenities that the owner chooses.

How do I get started with building an ADU?

Find a consultant such as a licensed contractor, ADU specialist, or architect to determine what type of ADU your lot is eligible for. A professional will explain what type and size of ADU you can build.

If you have any questions, please feel free to contact one of us:

Juan Huizar
[email protected]

Mark Malan
[email protected]

Louis Parada:
[email protected]

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