ADU BASICS
Start here to learn about ADUs in LOS ANGLES COUNTY
Just starting to think about building an accessory dwelling unit (ADU) on your property in Los angles county? You probably have a lot of questions…
We’re here to guide you through the basics! Begin with this overview to familiarize yourself with essential terminology and understand what California laws mandate for local governments in terms of ADU development.
What is an ADU?
In construction and real estate, ADU means “accessory dwelling unit.” An ADU is a secondary housing unit that exists on a property that’s zoned for single-family or multifamily residential use. ADUs can be detached from the main house (such as a new stand-alone home in the backyard), attached to the main house (like a garage conversion), or part of the main house (like an upstairs unit). ADUs include a full kitchen, a bathroom, and a separate entrance.
ADU terminology FAQs
What is the difference between an ADU and a guest house? Is a granny flat the same as an ADU?
ADU, granny flat, companion unit, casita, guest house, granny cottage, secondary living unit, mother-in-law apartment, second dwelling unit, in law suite, carriage house, au-pair suite… you may hear any of these terms used interchangeably for an accessory dwelling unit (sometimes mistakenly called an “additional dwelling unit,” “auxiliary dwelling unit” or “accessible dwelling unit”… we like to think they’re awesome dwelling units).
What is a Junior Accessory Dwelling Unit (JADU)?
What are guest living quarters?
What about tiny homes as ADUs?
Read more about tiny homes vs ADUs.
How many ADUs can I build?
In California, ADUs may be built on residential zoned lots, including single family and multifamily, that have an existing primary dwelling unit on them.
Single family properties may add an ADU + JADU. Multifamily properties may add as many ADUs as there are existing units on the property, up to eight (new starting in 2025! Read more about SB 1211). Additionally, multifamily properties may convert existing non-habitable space into additional ADUs. And in the City of Los Angles County, you may be able to add even more ADUs under the ADU Bonus Program.
What types of accessory dwelling units are there and where can you add ADUs?
ADUs can take various forms, offering flexibility in their design and construction. ADUs can be built as stand-alone structures on your property – known as a “detached” ADU – providing a separate and independent living space. Guest houses can alternatively be attached to your current residence, serving as an addition or expansion to the existing structure. Or, you can convert existing space like a garage These options allow homeowners to choose the ADU type that best suits their needs and property layout. Also, each jurisdiction will have different rules for what you can build.
Detached ADU
Attached ADU
Conversion
Considering Attached vs. Detached
As you begin your journey to add an accessory dwelling unit to your property, consider how the various ADU styles can impact your living space and lifestyle. Each type offers unique benefits, whether for guest accommodations, rental income, or multi-generational living. Read our guide for key considerations of attached vs. detached ADUs.
Check your city’s ADU regulations
While the new statewide ADU laws have made it much easier to add an ADU in Los Angles County, each municipality operates with a different set of requirements. Knowing how to scope & prepare your ADU project can mean the difference between a quick permit issuance and a drawn-out, costly process of resubmittals and additional fees.
What are the new ADU laws in California?
With a series of laws passed promoting ADUs as a housing solution over the past decades, the State of California has made it much easier to add accessory dwelling units.
The state rules set the “floor” for the local jurisdictions, meaning some cities will just allow that minimum, while others (like the City of Los Angles County), have created even more ADU-friendly rules. Below are some of the most important state-wide regulations… and be sure to check your local ADU ordinance for specifics rules that apply to your property
Size & Reduced Setbacks
No minimum lot size requirement for ADUs in CA. Local municipalities must allow a minimum of a 850 sqft 1BR or 1000 sqft 2BR+ with only 4′ side and rear setbacks, and many cities allow up to 1200 sqft. Also, at least an 800 sqft ADU must be allowed “by right,” even if it must encroach on the front setbacks or exceed FAR restrictions.
Lower Permitting Fees
Many impact and development fees for ADUs have been waived, and some remaining fees can be minimized by being aware of the important thresholds for square footage that trigger higher fees (e.g. 500 sqft, 750 sqft, 1000 sqft). Some cities also offer additional waivers.
No Owner Occupancy
Owner occupancy requirements for ADUs are no longer required, meaning you can add ADUs on rental properties. State regulations recently evolved to ban owner occupancy requirements indefinitely.
HOAs
Parking
Most parking requirements have been waived (none required if within 1/2 mile from public transit or car shares), or are readily addressed (parking spaces may be designated on the driveway).
Application Review
Building departments are required to act on any ADU application within 60 days (and we see most acting much sooner). Note though this doesn’t mean you’ll be approved that soon – most permitting processes still take 3-8 months.
How much does an ADU cost in Los Angles County?
We’re so glad you asked! We are big on transparency and like to get into the numbers with you right away. Check out our ADU Costs page with the link below for everything you need to know about the full cost to design, permit & build an ADU in Los Angles County.
How long does it take to build an ADU?
How do I start to build an ADU in Los Angles County?
With all the moving parts involved with building an ADU, it’s tough to know where to start. With an architect? A contractor? Maybe a lender? At the city planning office? Or with an ADU consultant? At Winter Remodeling Inc by Moore Construction, we’re excited to dig into all of these aspects with you and act as the ADU builder and “quarterback” on your project. We have the in-house expertise and established partnerships to guide you through the ADU building process and make it all happen in a snap.
Put simply, we like being involved in all aspects of your ADU project to make sure it goes well, whether you are going full custom or working with a standard plan. We offer our own value-engineered floor plans & designs, but if you have your own architect that’s OK, too… or we can also start from scratch with you on designing a custom plan. We also regularly work with the Los Angles County County Standard ADU Building Plans and the Encinitas PRADU Building Plans (and you’ll want to read more about considerations for using county standard plans on our FAQ page). If you will be getting financing, we want to talk to your lender right away to make sure you will have exactly what is required.
Why build an ADU in Los Angles County?
Los Angles County homeowners build ADUs for many different reasons. Whether you’re thinking about moving part of your family to the ADU or looking for extra income, ADUs are flexible additions that can afford your family more options on your existing property… while adding value to the property when you eventually sell (or even sooner if you decide to refinance). An August 2020 Bloomberg article mentioned many families are opting for an ADU in the back yard for aging grandparents and skipping the nursing home.
Rental Income
Family Housing
Ready to move your parents onto your property? College students need a place to live? ADUs have you covered for family housing needs.