Are you interested in building an accessory dwelling unit? We think it’s a great idea, which is why we’re here to help you navigate the considerable rules, regulations, and process guidelines that govern the construction of these innovative small affordable housing units under the Los Angeles ADU ordinance.
The first step in building an ADU (also known as granny flat and in-law unit) is determining whether or not your property is qualified. Until now, California’s ADU laws, which were first passed in 2017, might have seemed complicated for most homeowners to interpret. With California’s accessory dwelling units, allowable heights, parking space limitations, and other issues were so scattered that it was incredibly difficult to determine if an ADU could be built.
Fortunately, a new California second home law, AB 68, clears up many of the issues and creates a much more uniform set of standards. Here’s what you need to consider when building an ADU, based on the various Los Angeles ADU ordinances passed in the last three years.
The California legislature found and declared that allowing accessory dwelling units (ADUs) in single-family and multi-family zones provide additional rental housing and are an essential component in addressing California’s housing needs. In 2017 and 2019, changes to ADU laws further lowered barriers, better-expedited approvals, and expanded capacity to accommodate ADU development.
ADUs are a unique opportunity to address a variety of housing needs and provide affordable housing options for family, friends, students, the elderly, home health care providers, the disabled, and others. Additionally, accessory dwelling units offer the opportunity to maximize and integrate housing options within existing neighborhoods.
ADUs, in-law suites, and garage conversions offer benefits that address common development barriers such as affordability and environmental quality. ADUs are a type of affordable housing to build in California because they do not require any payment for land, major new infrastructure, structured parking, or elevators. ADUs are built with cost-effective one- or two-story prefabricated, modular, or wood structures. ADUs work great for couples, small families, friends, youth, and seniors.
ADUs also assist in addressing its various housing demands. Young professionals and students want to live in areas close to jobs, services, and schools. To address the needs of individuals or small families seeking housing in high-opportunity areas, homeowners can build an accessory dwelling unit, convert a garage, or convert an underutilized portion of their home.
This flexibility benefits not only the people living in the space but also the owner, in the form of additional monthly rental income or the ability to keep the family together.
The relaxed regulations and cost of building an ADU make it a very feasible and affordable housing option for students, elderly parents, young professionals, and seniors.
The cost of an ADU typically ranges from $70,000 to $200,000, including design, permits, and construction. The price may seem expensive up front, but an ADU is a long-term investment. Once you factor in savings on child care, senior housing, office rent, rental income, and increased property value, it’s easy to determine the return on your investment.
Because they provide multiple uses and cater to a variety of demographics, including students, young professionals, young families, individuals with disabilities, and elders, accessory dwelling units are a potent form of housing in California.
If there is no existing SFD or MFD on the property, or if an ADU with a new SFD/MFD is proposed, the City cannot act on the ADU/JADU until it acts on the SFD/MFD. The 60-days timeline will not start until the city acts on the SFD/MFD.
There are several different types of ADUs, with the main distinction being that some are attached to or within an existing building and others are stand-alone units.
In both cases, you must have at least four feet of separation on your property, which means there must be at least four feet of space between the edge of the unit and the property line. That’s a big deal for detached self-contained units in particular and represents the first real checkpoint for homeowners.
The exception: If you’re converting an old garage or other structure, or building from scratch in the exact same space, you don’t need to worry about setbacks at all. California garage conversion laws make building an ADU easy!
It should also be noted that you cannot sell an independent ADU separately from the main property. You can of course rent it out.
You must know about the ADU size limit, as you plan for your granny flat construction. The size regulations could vary on the precise nature of the construction, you plan.
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A detached ADU |
The unit can have 1200 square feet of interior space |
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An attached ADU |
The unit should have 1200 square feet of dwelling space or half the area of the main building whichever is smaller |
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A JADU |
The unit can at the most have 500 square feet of interior space |
There are also requirements for minimum interior space and how it is broken down. Unfortunately, if you were planning on building a giant bathroom in your ADU, you’re going to have to adjust your plans. The living room/bedroom must be at least 70 square feet.
The kitchen (along with the hallways and closet) must measure 50 square feet. The bathroom must be at least 30 square feet and contain a toilet, a sink, and a shower stall or bathtub.
Generally speaking, an ADU must be less than 16 feet tall. And if your ADU is under 16 feet tall and less than 750 square feet, your building permits can’t be blocked.
If you are building an ADU inside an existing home or building, the ADU can top out at the maximum height of the existing structure.
The size of your ADU is important, but just as crucial is the materials you use to build it. There are critical standards to ensure that granny flats represent high-quality housing options.
There are a plethora of exterior cladding options, but some are against regulations. Builders may not use one-piece composites, laminates, or interlocking metal sheathing. As for the roof, it cannot be made of wooden shingles. It must also have a minimum pitch of 2:12 for more than 50 percent of the roof area.
Meanwhile, windows must have at least double-pane glass and be labeled for building use, and cannot have exterior trim.
You can connect the ADU to your existing fuse box. However, there may not be enough space. If you intend to rent out the ADU, you must have a separate meter. Either way, there are a few thousand dollars worth of electrical work to be done here.
The ADU can share the water connection with the main house or have its own meter. Since separate metering would be expensive, we typically advise sharing the primary water connection for the home. The sewer line is not allowed to connect to the house. It must be connected to the sewer line downstream of the house.
Under the California Grandma Apartment Law, single-family homeowners can now build both a regular detached ADU and a smaller unit known as a Junior ADU.
A junior ADU is a smaller ADU that is part of an existing main building; you can extend the building up to 150 square feet beyond the original footprint of the house. In many cases, a junior ADU is a converted oversized bedroom or garage that includes its own bathroom and some kitchen appliances.
You are permitted to construct two full-size ADUs on the land if you own a multi-family house (provided you have the space for it, of course).
Thanks to AB 68, homeowners who convert their garages into ADUs (or tear down the garage to build an ADU from scratch) no longer have to replace lost parking spaces.
Additionally, there is now no parking space requirement for units built within a half-mile of public transportation.
If you’re in a historic area, you also don’t require a parking space.
Unless you’re an architect or engineer, the entire math gets pretty confusing. And unfortunately, you can’t just overlook it, given the sometimes complicated approval process that must be completed before any construction can begin.
For a homeowner to do this, he has to do a few things: he has to find someone to do the design work, he has to find a contractor to build it, and then he has to submit all of that for approval.
Approvals must come from the Department of Water and Power and the Department of Building and Safety. The whole process of creating the designs and applying for the permits costs around $6,000. So the owners are already into this for $6,000 before they know if they can build anything.
The difficulty of finding an architect and contractor, combined with permitting confusion, makes building an ADU a time-consuming and often cost-prohibitive process.
ADUs can be an elegant solution to a housing crisis and help increase property value, but the cost of a built ADU has been prohibitive…until now.
California State Code allows a detached ADU to be built up to 1,200 square feet. About 391 cities and counties use this state code, which means you most likely live in one of these areas.
However, cities and counties may impose their own restrictions on the size of ADUs, which means that other cities and counties have stricter ADU size rules.
About 150 cities and counties limit the size of their detached ADU based on their design plans. You’ll probably be limited to 1,000 square feet if you have a detached ADU with two or more bedrooms.
A detached ADU with one or fewer bedrooms is likely to be limited to 800 square feet due to factors such as lot size and coverage.
It is important to remember that this is just in general. Your specific city may have regulations that differ from those listed above.
As you probably already know, there are different types of ADUs. The following are the four categories of ADUs:
If you are converting an existing structure, such as a garage, there are generally no maximum size limits. This is because the structure already exists. If there are limits, the maximum size is usually determined by the largest accessory structure currently in the jurisdiction.
However, if you are converting a structure to a JADU (junior accessory dwelling unit), it must be less than 500 square feet.
If you are building an attached ADU, the general rule of thumb is that it cannot exceed 50% of the home’s square footage. It also cannot be taller than the existing house.
Internal ADUs are inside a home and are typically built into the existing floor plan. Therefore, there are not many general rules for them, only that they must be inside the pre-existing dwelling.
California State Code says that all ADUs must be at least 150 square feet, regardless of what type of ADU they are. However, there are exceptions. You can apply for a discretionary permit to build a smaller ADU, but you most likely won’t get approval.
According to the Housing and Community Development (HCD) Department of California: “A local government may apply development and design standards including, but not limited to, parking, height, setback, landscaping, architectural review, maximum unit size, that prevent adverse impacts on any real property that is listed on the California Register of Historical Resources.”
Therefore, the general state law can be regulated by individual local governments. As a result, 8 counties and 482 cities have created their own regulations within the state law that your community must follow when building an ADU.
This section of the law allows local governments to do things like relaxing restrictions by allowing ADUs larger than 1,200 square feet to be built. It also allows them to tighten restrictions by lowering allowable square footage and increasing spacing requirements.
The best way to find out the ADU laws in your specific area is to contact your local contractor or planning office and ask. Additionally, several localities have web pages that provide details on their ADU laws.
Although cities and counties may add rules and regulations on ADU sizes, there are certain gaps that must be considered.
The state law states that although local ordinances may have their own restrictions, exemptions need to be in place to allow people to build an ADU up to 800 square feet and less than 16 feet in height.
So, if lot coverage requirements limit you to an ADU under 800 square feet, you can still build one that big as long as there are 4-foot setbacks in the back and side yard and it doesn’t exceed a height of 16 feet.
You might be tempted to go big if you want to construct an ADU in California. However, we recommend building your ADU below 750 square feet. ADUs less than 750 square feet are exempt from lot coverage, open space, and minimum lot size requirements.
Being exempt from these regulations can make your planning and development process much easier.
Additionally, ADUs smaller than 750 square feet are exempt from impact fees, making building an ADU yourself a less expensive endeavor.
If you live in one of the cities or counties that have very strict size limitations, you may need help making the most of the space you have. Here are some tips and tricks for building an ADU that doesn’t feel cramped.
Although windows take up valuable wall space, they also provide plenty of natural light. No one wants to live in a small, dimly lit area. The more natural light you let into a room, the cozier it will feel. Also, the windows help with the illusion that the space is larger than it really is.
Storage is key. Whenever you can make use of an area for extra storage, do so. The more belongings that are stored in the storage areas, the less clutter there will be in the unit. The messier a unit is, the smaller it feels. There are some ADU furnishings and equipment that are made expressly to optimize storage.
Finally, during the design stage, think about what is necessary and what is not. Ask yourself questions like:
Be sure to review some of the most common ADU mistakes before deciding on your final ADU design.
If you don’t want to go through the rules and regulations regarding building an ADU all by yourself, you should work with an ADU contractor. They can help you understand your city/county size limit regulations and help you obtain the necessary permits to build your ADU.
When building your ADU, it is critical to adhere to sizing regulations. Your plans will not be approved by your local government if they do not comply with all regulations and requirements. Therefore, it is important to consult your city/county sizing regulations before beginning your ADU design and planning.
Yes, you can have a second-story ADU within your property in California.
The regulations offer the scope to have an ADU and JADU within the property.
You are allowed to rent your granny flat to tenants. However, the authorities discourage short-term rentals and you can only lease this space for more than 30 days.
