What You Need to Know about Accessory Dwelling Units (ADUs): The ADU FAQ
As society, the economy, living habits and environmental awareness change the way we live, accessory dwelling units (ADUs) are making a big comeback. Here’s what you need to know about them:
What is an Accessory Dwelling Unit or ADU?
An accessory dwelling unit is a fully functioning living space with bathroom facilities, bedroom and kitchen. It is a small, self-contained residential unit located on the same lot as an existing single-family home. An ADU can be a remodel of an existing interior space, an attic dwelling, a basement apartment, an addition attached to the house or garage, or a separate dwelling located on the property.
You may have heard other names attached to accessory dwelling units like “granny flat”, “guesthouse”, “mother-in-law suite”, “backyard cottage,” etc. Legally speaking, an accessory dwelling unit cannot be bought or sold separately (like condominiums), and either the main house or the ADU must be occupied by the owner.
ADUs have a long history, and although they fell out of favor somewhat during the mid-1900s, they are seeing a significant rise in popularity again in the 21st century. There are several factors behind this:
California continues to be in the throes of a major housing crisis
Homeowners want space for family or guests that allows them to live independently on their property.
Environmental awareness makes smaller homes a good idea for the planet.
Property owners want to maximize and improve land use, particularly in areas that are already overdeveloped.
In short, this is a way for homeowners themselves to boost the availability of affordable housing options for their family and friends.
Is an Accessory Dwelling Unit Right for Me?
There are a variety of ways you can use an ADU, and its functions can change as your needs evolve. Here are some ways that people are using accessory dwelling units today:
Home office space
A private guest house for visitors
To rent out as an apartment to individuals or couples
To accommodate a family member with special needs
To accommodate aging family members who want to live independently, yet close to family
A starter home for adult children
Naturally, adding a free-standing or attached ADU to your property or home will demand a great investment of money and time, but the benefits once the unit is complete can offset the initial costs. As ADUs are significantly smaller, they cost far less to operate and maintain (per square foot) once they're finished. If you rent the space, this income can also help with retirement savings and mortgage costs. As a homeowner, an accessory dwelling unit can also significantly increase your property value. And having the flexibility of an adaptable, additional living space on your property can give you more options as your family’s needs change over time.
How Do I Start an ADU?
If you’re a homeowner who wants to optimize your existing property with an accessory dwelling unit, it is absolutely essential to get professional help. You will need to work with an experienced, qualified design/build firm that is fully informed on the latest state and local building codes, permits and regulations. You’ll also want a design/build team with impeccable taste that can deliver your ADU on time, on budget and with a great sense of style.
What Types of ADUs are There?
We’ve mentioned several types of ADUs so far, but they generally fall into these three major categories: interior, attached or detached.
Interior ADUs—Located in the primary dwelling, it is built from existing, converted space, usually in the attic or basement.
Detached ADUs—A separate, exterior, stand-alone structure on the main home’s property, like a cottage or detached garage.
Attached ADU—These are built as an addition to the primary home structure.
What Does an ADU Cost?
ADUs can vary widely in cost, depending on a host of factors:
Is it an interior ADU, detached or attached?
How big is it and where is it located?
What finishes and amenities do you want to add?
Many ADUs are really tiny houses that contain most of the same elements as a regular home, just constructed into a space-saving design on a smaller footprint. A general, ballpark estimate for a 200 square foot interior ADU is about $150,000. Again, this budget number can vary widely depending on the type, design, size, and other aspects of the ADU.
The best way to get an ballpark estimate is to talk with your design/build firm about what your specific needs are.
How Does California Law Impact ADUs?
California State laws have permitted the construction of ADUs, but there were also many individual local ordinances that have affected ADUs. In the past, the local laws complicated and added requirements for homeowners who wanted to build new ADUs. Some of the most frequent requirements included city and county-level standards regulating construction, utility fees, lot coverage and parking.
The good news is that Governor Jerry Brown recently signed three new ADU-related pieces of legislation with the hope of addressing California’s ongoing housing crisis. These new laws can make it easier for homeowners across California to get permits for new ADUs from their city and county offices.
Homeowners should be aware of the following legislation impacting ADU construction across California:
Senate Bill (SB) 1069—Significantly reduces, and in some cases eliminates, ADU parking requirements and utility hook-up fees. This bill also accelerates the approval process for ADUs attached to the primary home.
Assembly Bill 2299—Requires local ADU ordinances to include non-discretionary and ministerial approval for second-unit construction that meets city building requirements.
Assembly Bill 2406—Speeds up the permitting process for homeowners who want to turn an existing room in their home into an attached ADU, such as a studio apartment.
These laws were designed to prevent local governments from bogging down the process for homeowners who want to construct ADUs, limiting city and county authority to regulate ADUs over state law. All local governments were required to adopt ADU ordinances that follow these new state requirements as of January 1, 2017.
Better still, the new California State laws will help accelerate the ADU construction approval process, eliminating secondary utility hook-up costs usually paid by the property owners. As for the parking requirements, the state laws remove these for ADUs located close to public transit lines, and lessen the requirements for other areas.
Naturally, laws and codes can change, so if you’re thinking of having an ADU added to your property, it’s a good idea to keep an eye on the latest information regarding California’s ADU laws.
Local ADU Ordinances
Gayler Design Build stays informed of all changes and updates to local zoning ordinances that impact ADU construction in Contra Costa County, as well as the following locations where we have worked with homeowners on building accessory dwelling units in the following communities:
If you are considering adding an accessory dwelling unit to your home or property, please contact Gayler Design Build to discuss your ideas and find out all the latest news on ADU construction in your community.