ADUs in Los Angeles: Top 50 Frequently Asked ADU Questions

ADU FAQ – 50 Most Popular ADU Questions

Building an ADU has become more and more popular recently, yet a lot of people don’t know much about them. If they do, they only know the very basics, like what it is and the different types of ADUs. With all of the new regulations for 2020, we’re getting hundreds of ADU questions regarding guidelines, costs, the construction process, and more.

Here at GreatBuildz, a free service that matches homeowners in Los Angeles, Orange County, Ventura & San Diego with reliable, thoroughly screened General Contractors, we ensure that no questions will be left unanswered during the complete process of building your ADU. 


Q: What is an ADU?

A: ADU stands for Accessory Dwelling Unit. It is a second structure on a property that can be used as a separate home, including bedrooms, bathrooms, and a kitchen. This is easily the most asked of any ADU questions. See more about ADU definition here.

Q: Did the State laws recently change with regard to ADUs?

A: Yes, California passed new ADU laws in 2018 and again in 2020 that made it easier to build ADUs throughout the state.

Q: Why are Los Angeles homeowners building ADUs?

A: There are many potential uses for an ADU, these include:

  1. Investment – rental income
  2. To house family, especially retired/senior parent(s)
  3. A dedicated office or Work From Home space
  4. Living quarters for a nanny/guest
  5. As a fitness/music studio
  6. For retirees to live in so they can rent their main home, etc.

Q: Why are ADUs becoming so popular?

A: ADUs are currently an extremely popular project in Los Angeles due to their flexibility of uses. Also, it’s generally cheaper to build an ADU than to buy a home with more space (on a per square foot basis). Currently, there are over 15,000 ADUs in various stages of planning and construction in Los Angeles. Ironically, This has become one of the most popular ADU questions.

Q: What kind of ADUs are there?

A: There are generally three types of ADUs:

  1. A garage conversion into an ADU
  2. A new detached ADU
  3. A new attached ADU – you can find more info on my ADU Overview blog.

ADUs in Los Angeles: Top 50 Frequently Asked ADU Questions 1


Q: What kind of property qualifies to build an ADU?

A: Any residentially zoned property – single-family or multifamily.

Q: Is there a minimum lot size necessary to build an ADU on your property?

A: No, there is no minimum lot size.

Q: Where on my property can I build an ADU?

A: The ADU must typically go in the backyard. It must be located at least 4 feet from the rear and side property lines (unless converting an existing garage). It can be fully detached or attached to the main house or to a garage.

Q: What size ADU can I build?

A: You can build up to 1,200sf if detached. If attaching an ADU to your house, it can be the lesser of 1,200sf or 50% the size of the main unit. It can be either one or two stories.

Q: Do I have to provide parking for an ADU?

A: No parking is required for an ADU, as long as you are located within one-half mile walking distance of a public transit stop.

Q: Can I rent an ADU to a tenant?

A: Yes, you can rent an ADU to a tenant.

Q: Can I sell an ADU without my house?

A: No, you can’t sell an ADU without your house.

Q: Must I live on the property?

A: No, you can rent both the main house and the ADU. The owner-occupancy requirement has been waived for ADUs until at least  2025.

Q: Do ADUs require pedestrian access from the street?

A: Yes, a walking path access of 3’ wide is required from the front yard/sidewalk to the ADU (a driveway is acceptable).

Q: Can I build an ADU on a duplex, triplex, or other multifamily property?

A: Yes, but there are unique restrictions that pertain to multifamily properties. Please review my blog specifically about ADUs on multifamily properties to learn more.

Q: I have a unique property or situation, where can I get advice to determine if I qualify to build an ADU?

A: You should consult with an experienced ADU architect/designer or speak with the LA City Building Department (Zoning Section) located at You can also review the city’s memorandum on ADU regulations at

Q: What is a JADU?

A: JADU stands for Junior Accessory Dwelling Unit. A JADU is a dwelling unit that can be built within the ‘envelope’ of an existing home (ie. inside an attached garage or bedrooms). A JADU is limited to 500sf and comes with some other limitations (Learn more in my JADU section of this blog).

Q: Can I build both an ADU and JADU on my property?

A: Yes, you can build both an ADU and JADU on any single-family property – however you should know there is still an owner-occupancy requirement for JADUs.

Q: Can my Homeowners Association stop me from building an ADU?

A: According to the most recent state laws, an HOA & CC&Rs cannot preclude you from building an ADU. (A Homeowners Association is an organization in a neighborhood, condominium, or other jurisdiction that creates and enforces rules for the residents and their properties.)

Q: Can I still convert my garage into an ADU if it is located less than 4 feet away from my property line?

A: Yes, an existing garage location is “grandfathered-in” as long as it was legally permitted when it was originally built…and it can be converted into an ADU regardless of the setbacks.

Q: Where do I start if I want to consider building an ADU?

A: You’ll want to start researching the costs and viability by doing a little research like reading our other blogs and other resources online. Next, you’ll want to speak with both an architect and contractor experienced with ADUs to get guidance specific to your property. Greatbuildz can provide recommendations on both of these and help with any ADU questions.


Q: How much does it cost to build an ADU?

A: That depends on whether it’s a garage conversion or a new-built ADU.  A standard 2-car garage conversion will usually cost $70,000-$100,000 but can be less or more depending on your needs.  A new build ADU will usually range $300-400 per square foot. The bigger the ADU size, the lower it will be per square foot. If you’re considering building a 2-story ADU, or an ADU on top of a garage, you should know the cost range is typically on the higher end of the price-per-square-foot. As you can imagine, this is one of the most common ADU questions we get.

Q: How much does an architect charge for ADU plans?

A: Depending on the size and complexity, full ADU plans should cost between $4,000-$12,000.

Q: What kind of city fees do I have to pay to build an ADU?

A: According to the latest state laws, cities are not allowed to levy impact fees on an ADU under 750sf. You will just need to pay plancheck and permit fees to the building department; which are often a few thousand dollars. Some independent cities. including Santa Monica and Culver City, may have higher fees than LA city.

Q: Are there ways to save costs when building an ADU?

A: A garage conversion is the most affordable ADU. Also, see my other blog for 5 ways to save when building an ADU.

Q: Are there ways to finance the costs of an ADU?

A: Yes. The options include getting a HELOC (home equity line of credit), A cash-out refinance, a construction loan, or a renovation loan.

Q: What are some ‘not so obvious costs’ of building an ADU?

A: Don’t forget about the ‘soft costs’ that include designing and processing the plans with the building dept. as well as city plancheck and permit fees. In terms of actual construction, often overlooked costs are fencing, landscaping, concrete patios, and utility trenching repairs.


Q: How long does it take to build an ADU?

A: Construction of a garage conversion will take 2-3 months, while building a new ADU might take 4-6 months depending on size.

Q: How is an ADU built?

A: Several ways. Most often, it’s built like a traditional wood-frame home right on site. Also, there are modular (pre-fab) companies that build the entire ADU in a factory and assemble it (or crane it in) onsite. Finally, there are other unique solutions like ADUs constructed from recycled shipping containers, etc.

Q: Are modular or pre-fab ADUs cheaper?

A:  Not always. Although the price from the factory is often cheaper than from an ADU contractor, this price often may not include transportation or craning, and more importantly the foundation and utilities. Granted, you might get a different answer if you ask a pre-fab ADU company these types of ADU questions.

Q: Is an ADU like a small house?

A: Yes, an ADU is essentially a smaller version of a home, so it’s not a minor project. It needs all the same utilities (water, sewer, electric gas) and all the same comfort and safety requirements. Because it’s a serious project, we do not recommend hiring a handyman or unlicensed contractor for this project.

Q: Can I legalize an unpermitted Accessory Dwelling Unit or garage conversion?

A: Yes, but you will need to bring the ADU up to code and pay for the construction that is required. For these types of ADU questions, a good contractor can look at your property and give a rough estimate of the costs involved.

Q: Can I connect ADU utilities to the existing home?

A: You can connect electrical service to your home, but the city will require you to connect your sewer line directly to your lateral in the front yard and your water line to your water main.

Q: Can I build an ADU above my existing garage?

A: Yes, however, it’s likely your existing garage wasn’t built to support a second floor, so it will require additional structural and/or foundational support to be constructed before adding the second story.

Q: Where can I get a construction checklist of what items go into building an ADU?

A: You can get a construction checklist in our blog: Building An ADU? This Construction Scope Checklist Will Keep Your Bids Consistent

Q: Can I have separate utility meters for the ADU?

A: Yes, you can have separate meters for water and electric service but it will cost more to install. You can also investigate installing ”sub-meters” as a lower-cost alternative.

Q: What improvements do I have to make to my garage to convert it into an ADU?

A: That depends on the age and condition of your garage. A good contractor can give you specific guidance, but in general, you may have to add structural supports to your garage framing, and you may need to deepen portions of your garage foundation.

Q: What’s the best way to find an ADU contractor?

A: Because an ADU or garage conversion is a major project, it’s not a good idea to hire a handyman or unlicensed contractor. Look for reputable, licensed & insured contractors with ADU experience. Check out this blog for further guidance on how to find an ADU contractor. Or call GreatBuildz to be matched with pre-screened ADU contractors.

ADUs in Los Angeles: Top 50 Frequently Asked ADU Questions 2


Q: Does building an ADU on a single-family property make my home subject to rent control?

A: Maybe. It’s unknown exactly how this will play out. Because the ADU is new, it shouldn’t be subject to rent control, however, the main house ( if it was built prior to 1978) could be subject to rent control if it’s rented out. See this link:

Q: Will my property tax go up if I build an ADU?

A: Most likely, the tax assessor will increase the value of your property to include your new ADU but will not re-assess your existing home. Check out the Assessor’s website for more info.

Q: If I have DWP power lines at the back of my property, where can I build an ADU?

A: A new accessory dwelling unit or garage conversion which is more than 10’ away from the edge of the powerlines is acceptable. An ADU within 10’ of the powerlines must file for a DWP encroachment permit (current processing time is 2-3 months). A garage that is currently under the powerlines may have more difficulty being legally converted to an ADU.

Q: Is building an ADU a good investment?

A: This depends on several factors, but it can be a good investment because you’ll get cash flow from renting it PLUS it adds to the value of your home when you go to sell.  See more guidance on my blog for real estate investors.

Q: Where can I find more resources about building an ADU?

A: You can check out our other blogs that go into more detail or find other resources at

Q: Can my ADU have a separate address and mailbox?

A: Yes, Los Angeles can issue you a separate address for your ADU.

Q: How large should I make my ADU?

A: That depends on how you plan to use it. You’ll probably have just one kitchen, one dining area, and one family room, so the decision really comes down to the number of bedrooms and bathrooms. As a rental unit, more bedrooms equate into higher rent.

Q: How do I ensure that the ADU & main home maintain their own privacy?

A: This is important to consider, especially if the ADU will be tenant-occupied. Build your fencing in a location that allows outdoor space for the ADU resident and also separation/privacy between the two homes would be a good idea.

Q: Are ADUs good for seniors and retirees?

A: Yes, and they are even sometimes called “Granny Flats”.  Their small size is ideal for a retired single person or couple. People are building ADU’s in their yard specifically to house their aging parent(s). See our blog for more info on granny flats for seniors.

Q: Does building an ADU turn my property into a duplex?

A: Not officially because the zoning of your property doesn’t change. But for all intents and purposes, you will have a duplex-like property with two units you can rent. Learn more in our blog post about how to turn your home into a duplex with an ADU.

Q: Are ADUs good for first-time buyers in Los Angeles?

A: Yes, they can be advantageous for first-time buyers who might struggle to pay the high home prices in LA. By buying a home, building an ADU, and renting it out, first-time buyers can use this rental cash flow towards their mortgage, thereby reducing their monthly housing costs.

Q: What kind of appliances do I put in an ADU?

A: In the kitchen, you need a fridge, range & microwave (or microwave/range hood combo). You should look for appliances that are smaller than the standard size used in a house. A dishwasher is nice if you have the room for it in the kitchen. Ideally, you’d create a space for a washer & dryer (a stackable unit fits well in an ADU)


Any ADU questions we missed? Call or text us at 818.317.3567

When it comes to planning and coordinating an ADU for your home, you shouldn’t have to go it alone – GreatBuildz can help simplify your renovation experience. GreatBuildz is a free service that connects homeowners in Los Angeles, Orange County, Ventura & San Diego with reliable, thoroughly screened general contractors and provides project support from start to finish. Call now (818.317.3567) to chat with a real person about your next renovation project or visit our website for more information:

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