Get Answers About Your ADU

Generally, you will be able to build at least a 1000 sqft ADU, and up to 1200 sqft in some cases. Read our guide to ADU size maximums and see city-by-city ADU regulations here.

There are no minimum lot sizes for accessory dwelling units per California state code. Even if there is a coverage ratio maxed out on your property, you are still allowed to build at least an 800 sqft ADU.

Under California state law, new ADUs must be at least 4 feet from side and rear property lines. If you’re converting an existing, permitted accessory structure—such as a garage—no setbacks are required. You can even rebuild on the same footprint and roof height, even if the old structure had reduced setbacks.

Some cities require a minimum distance between an ADU and the main house, typically 5–10 feet. In Long Beach, there’s no listed minimum, but fire codes still apply—so we usually keep at least 6 feet for safety.

Yes, you can generally build an ADU in your front yard if it complies with underlying setbacks for your lot. A local agency may still apply front-yard setbacks for ADUs.

However, front-yard setbacks cannot preclude an ADU of at least 800 square feet and must not unduly constrain the creation of all types of ADUs (Gov. Code, § 65852.2, subd. (c) and (e)). To successfully argue for an ADU in the front yard setback, it would have to be the case that nowhere else on the property can accommodate an ADU. 

We have seen this happen when there is only one yard to the property (e.g. a side/front yard). But if you just want to build in the front to preserve your large back yard? It’s unfortunately not possible unless the ADU conforms to the front setback.

If your ADU is under 500 sqft, it will not require civil engineering review (stormwater, catch basins etc). If your ADU is under 750 sqft, you will not incur impact fees (except for the school fees which are still due even after the new regulations).

New state laws permit two ADUs on a single-family zoned property… one full Accessory Dwelling Unit (ADU) and one Junior Accessory Dwelling Unit (JADU). On multifamily properties, you can build up to two detached ADUs. 

Yes. Though from a feasibility standpoint, starting from scratch will often be easier and cheaper. Trying to tie into an existing outbuilding can be problematic, especially when it comes to footings and having proper compaction. Grading work done decades prior is not up to par with current standards. When we dig the footings for the new structure up against the existing, often we cannot get compaction and are exposed to settlement issues.

An ADU is a designation that can’t exist by itself – there must also be a primary residence – so the initial home will be considered the primary residence. Then, once you build the second, larger home, you would then “convert” the status of the original building to an ADU. This means you would need to ensure the first structure you build (what you would later call the ADU) will conform to both the requirements for a primary dwelling AND the requirements for an ADU. 

Yes, you can build an ADU in a historic district or on a property subject to historic preservation, such as under the Mills Act. While local agencies may impose standards to protect historic resources, these standards must be objective and cannot overly burden the creation of ADUs. California State ADU Law ensures that historic preservation requirements do not prevent compliant ADU projects.

We have an entire page devoted to explaining ADU build costs. Read more about all of the costs that will go into designing, permitting & building your ADU… we want you to know about all the potential costs before you get started.

The cost would be around $120K for a standard garage conversion project of about 400 sqft. We no longer handle conversion work as we are focused on becoming extremely effective at building standalone ADUs.

Prior to Jan. 1, 2020 when new ADU and affordable housing laws went into effect, cities could charge development and impact fees that could total $15,000-30,000. However, with the passage of recent state laws, impact fees on ADUs less than 750 square feet have been eliminated. 

Fees on ADUs 750 square feet or more must now be proportional to the size of the ADU relative to the primary dwelling unit. ADUs will still trigger sewer connection fees and capacity fees, but those fees must also be proportionate to the size of the ADU. In total, permit fees have been reduced to $5,000-12,000 on average (or about $10/sqft of the ADU size). 

We will give you a high-level estimate in our first phone call based on your description of the project and your site. If we determine your project is a fit, we issue a proposal that includes your expected price for each phase of the project, including design, sitework, and construction. 

If you do move forward with ADU Homes, we finalize your ADU build price during our first step of Feasibility & Design so that you know the full cost of your ADU upfront; we absorb the risk of labor & material price fluctuations. We work hard to refine your budget so we minimize surprises over the entire process.

Yes, we are happy to look at your ADU plans to see if we can offer a proposal to build, though most of our work is design/build.

You can, but we typically don’t find clients can save a lot of money by doing so. We have trade agreements in place with suppliers, which help us provide our clients very competitive pricing on finish items – often at the same or better pricing than could be found elsewhere. 

Additionally, we have already screened materials to ensure the specifications will work together. However, if you want to provide your own finish materials, that is something we accommodate during the Selection process. You can either provide the items yourself, or work with our vendors to source custom materials.

There are a variety of financing options available from HELOCs to private lenders, which we discuss on our blog.

No, but have lenders we can refer you to. We work closely with you and your lender to ensure you have the required plans, scope of work, and budget required to submit for loan documentation. If you don’t already have a lender, we are happy to put you in touch with some contacts and help you through that process.

Once you fill out a brief Project Assessment, we get into the details with you right away to make sure your project is feasible and that your vision is aligned with your budget. Read about our overall process from the time we first interact to the time we hand you the keys. Also read about our user-friendly interface, BuilderTrend, where we manage your entire project.

Yes, we are happy to answer feasibility questions, provide ballpark estimates, and get into details quickly about your property specifics so you can decide if an ADU project is right for you and, more specifically, if you’d like to work with us. Contact us to get started on the free discovery process.

Yes! We offer custom, standard, and semi-custom plans. 

No, in fact, we offer the most competitive pricing if you pick from our standard plans, or work with us to customize an existing plan to suit your needs. You can also provide us with a sketch of your ideas or your “wish list,” and we will design something custom for you.

Our primary focus is on design-build projects, providing an integrated, end-to-end experience for our clients. While we don’t exclusively offer design & permitting services, if you’re open to considering the complete design-build approach, we’re here to guide you every step of the way. And why choose a design-build general contractor like ADU Homes over separate teams of professionals? Here’s a snapshot of the benefits:

• Accountability: Our singular focus on design-build ensures seamless project execution. We are entirely accountable, aligning with the commitments made during the feasibility study.
• Transparent Budgeting: Our approach centers around clear budgeting. We provide an unambiguous view of the complete costs right from the outset.
• Guaranteed Price: With ADU Homes, you get a fixed build price. This ensures budget predictability with no surprises.
• Efficiency: Our in-house permitting team ensures that the project moves swiftly and efficiently, eliminating potential delays that can arise from multiple handoffs.
• Quality: A collaborative, unified team means that the end result will be of the highest standard.
• Cost Savings: A significant number of projects encounter cities that may misinterpret ADU regulations, leading to unnecessary costs. Our seasoned team is well-equipped to advocate for you, ensuring you aren’t paying more than you need to.

We are a licensed general contractor and provide a design/build service, meaning you work with us for your entire project and we are fully accountable. We will be on point for getting the job done during design, permitting and in the field. 

We subcontract out trades like concrete, framing, drywall, plumbing, electrical, HVAC, tile & stucco. We also partner with select consultants such as geotechnical engineers, civil engineers, and structural engineers for the design phase of the project. All the rest of the work is done in-house by our team, including design & permitting.

We design and build ADUs throughout Los Angeles and Orange Counties. Check out our ADU Regulations page for the requirements in your municipality. 

Our ADUs are “stick built” construction and are not prefab ADUs, mobile or manufactured homes. All of our ADUs are built on-site using conventional framing methods, though we utilize some off-site processes that improve our quality control and timeline. We regularly evaluate new technology to make sure we are offering a competitive product.

In a world where versatility is often praised, there’s still immense value in specialization. We have made a deliberate decision to focus solely on detached ADU (Accessory Dwelling Unit) design and build for several key reasons:

1. Expertise Through Specialization: By dedicating ourselves exclusively to detached ADUs, we’ve refined our skill set to become true experts in this niche area. This enables us to maintain the highest quality standards and keep up with the latest best practices, ensuring our clients receive nothing but the best. From initial planning and design to the final stages of construction, our in-house team collaborates seamlessly, ensuring a cohesive and efficient project flow.
2. External Elements Can Be Managed Post-Completion: While elements like landscaping, patios, or other auxiliary structures can enhance the overall aesthetic and functionality of a property, they are not integral to the ADU construction process. These components can be executed after our work is done. We’ve found that many homeowners have preferred vendors for such tasks or may even choose to undertake some projects DIY-style. By allowing homeowners the flexibility to manage these elements separately, they often find opportunities for cost savings and personalized touches.
3. Home Additions and Remodels Present Unique Challenges: Working on additions or remodels is fundamentally different from constructing a detached ADU. Such projects require extensive coordination with existing structures and conditions, which can be unpredictable and may lead to extended timelines and unforeseen expenses. Our commitment to transparency, predictability, and excellence means we avoid venturing into areas that could compromise these values.

Yes, ADU Homes provides comprehensive warranties as part of our construction agreement. Our commitment includes:

• 1-year Full-Service Warranty on all workmanship and materials we manage or procure, ensuring adherence to the NAHB Residential Construction Performance Guidelines – Fifth Edition. This warranty covers defects not caused by normal wear and tear or homeowner neglect.
• 2-year Full MEP Warranty on all mechanical, electrical, and plumbing (MEP) systems, including solar/photovoltaic systems
• 10-year Structural Warranty against structural defects, contingent on our adherence to approved plans and specifications.

A soils report is an optional step in most jurisdictions. Declining a soils report means that no soils compaction testing will be performed by a Geotechnical Engineer, and the ADU will be built to the most stringent UBC design standards & thresholds. In such cases when a soils report is declined, ADU Homes will not be responsible for issues stemming from insufficient soil conditions.

The entire process from signing a proposal to moving into a completed ADU takes 7 to 9 months.

Cities must act on an application for an ADU within 60 days of receiving the application in cases where there is an existing single-family dwelling on the lot. 

We are also seeing some cities enact “queues” for review, especially when they are facing staffing crunches like many industries are right now. We keep our clients updated on what to expect in their city.

In short, the answer is no. State laws passed in 2020 made obtaining a new ADU easier with “ministerial approval,” which refers to a streamlined permit process for development approval involving little or no personal judgment by the public official. 

The official’s “discretion” on whether to approve the permit has been eliminated, as well as factors such as design features and size. Thus, only the municipal code or state laws will be considered in the approval process. 

A plan must still be formally submitted to the city and reviewed to confirm the plans adhere to state and local ADU laws, building code, etc.

Permitting with the city still takes a big chunk of time. The build-out is another large chunk of time. It’s a process that includes hundreds of decisions, so even losing half a day on tasks can add up significantly. 

This is why we manage all our projects utilizing BuilderTrend to communicate seamlessly with the client, vendors, subcontractors, and within our team.

Yes, when we discuss your project, one of the first steps is to assess the existing conditions of the property. We work with a provider that licenses a large data set that includes lot dimensions, land use, lot square footage, building square footage, zoning and more. 

This is cross-referenced with plot plan information and several different sources of satellite imagery to ensure accurate lot dimensions. When matched up with ADU regulations for your lot, this enables sufficient accuracy for us to position a chosen ADU floor plan on your site plan for the purposes of a Proposal.

When you decide to move forward, the first part of our project with you will be to verify all of our assumptions by going on-site to measure existing utilities, assess required upgrades, and ensure that the site assumptions we made were accurate. 

We will also refine your site plan, floor plan, elevations, and electrical plan based on all these inputs. You will review and sign off at this phase to lock in your pricing and authorize us to move on to your full set of construction docments for the city.

It depends on your city’s requirements, site conditions, and where your ADU will be placed. Some jurisdictions now require a boundary survey for all ADUs, while others leave it up to the building inspector, who may request one even after permitting, causing delays. 

To avoid surprises, ADU Homes includes a basic planimetric/topographic survey in all our projects. If your ADU is within 2 feet of a setback, a boundary survey may also be required. 

Many cities in LA and OC have made several ADU plans publicly available. State-wide, as of January 2025, California municipalities must begin accepting pre-approved plans.

Sometimes. If you can use a plan exactly as-is, you may not need to pay for architectural plans. You will also still need a site plan along with Title 24 calculations. And lastly, since most of the costs of your ADU project are in the actual sitework and build-out (not the design phase), the few thousand you may save on plans may vanish because of higher build costs.

Any newly constructed ADUs may only be rented for periods of more than 30 days. This is a state-wide requirement designed to curb ADU usage for short-term rentals. A city cannot issue a building permit until you have signed a covenant that agrees you will not rent the ADU for less than 30 days. 

You do, however, have the option of moving into the ADU and renting out your primary residence as a short-term rental (you should confirm the short term rental rules for your jusridiction). 

Yes. Per state ADU code, if you have a structure of two or more residential dwellings that are attached (e.g., a duplex) and in a residential zone, you may add two detached ADUs. 

You can also convert accessory space within the existing structure to an ADU. Read more about adding ADUs to multifamily properties.

No! Owner occupancy requirements have been permanently banned by the State of California (AB 976), meaning you could add an ADU on a rental property. This is not the case for JADUs, which do have an owner-occupancy requirement. 

ADUs do not require parking if they are within a half mile walking distance of public transit or created within an existing space in your house or an accessory structure, like a garage or carport. Additionally, no replacement parking is required for the main residence when a garage or carport is demolished or converted to create an ADU. Otherwise, parking requirements for ADUs are one parking space per unit or per bedroom (whichever is less). JADUs do not require parking.

Typically, cities have accepted showing replacement parking in the driveway. We can also convert existing landscaping to parking, so long as this parking does not exceed the lot coverage allowed per the zoning.

Neither HOAs (Home Owners Associations) nor property CC&Rs (Covenants, Conditions and Restrictions) can “reasonably prohibit” development of an ADU or JADU. However, they can make it more time-consuming and expensive for you. 

Until recently, an ADU could not be sold separately from the primary residence due to California state law. However, AB 1033 lets cities and counties decide whether to offer the option of condo conversion in their jurisdiction. This is a new development as of Fall 2023. 

Yes, an ADU is typically designated with a separate address for fire safety reasons (so the fire department would know where to go).

Yes, an ADU will receive a separate electric bill. This is because all ADUs must be metered separately for electrical service. Water service can be metered privately by means of a metering device that is located on the ADU. 

Yes, the state will conduct a “blended assessment” to determine your taxes. This means the base value of the existing house will stay the same, and your ADU’s additional value will be added to the existing home’s value. 

Once this new assessed value for the ADU + property is set, the property value will then be taxed at 1-2% annually. This is generally an increase of $2-4K in taxes a year for a typical ADU. 

Probably yes. Getting a permit for an ADU in the coastal zone is becoming much more likely, though the process may take time. Usually, if there is a Local Coastal Program (LCP) in place by the city to handle low-impact Coastal Commission projects, then it can be handled by the LCP at the city level. 

LCPs are catching up to state ADU legislation in favor of ADUs, though in some areas, restrictions are still more stringent (e.g. bluff top size, hillside overlay zone, wildland urban interface etc). 

When you build your new ADU, you may have to address permitting for any “illegal” or unpermitted ADUs on the property. The process is similar to bringing an illegal addition into compliance. 

It would require drawing a plan for the existing structure (typically $2000-3000), sending it to plan check at the city (planning, building, and fire), potentially conducting an exploratory phase where walls are opened up for inspection with the city (typically no more than $1000-2000 for opening walls and repairing them), addressing anything in the structure that is not within compliance (cost will of course depend on what’s going on with your structure), and paying for any permits (typically $1000). 

Any tenants in your existing ADU likely will not need to vacate during this process.

Consider the visibility you will have into the project. How does the company handle project management? What tools will enable you to stay up to date on progress? How easy is it to work with the company on things like payments and material selections? 

Pick someone you trust & will be excited to interact with about your project regularly… it should be a pleasure to discuss your project, not a chore. It’s also important to engage a contractor early on to provide cost analysis and make sure you are designing within your budget. 

We are always looking for great new trade partners. Contact us to see if there is a good fit with ADU Homes.

We are always looking for realtors to collaborate with on ADU opportunities. Contact us to see if there is a good fit with ADU Homes.