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Can You Build An ADU Before The Main House In California: Regulations, Permits, And Process 

Find the answers you need to the question of whether you can build an ADU before the main house in California. In this blog post, we delve into questions around regulations, permits, and processes relating to this unique scenario. We will provide essential guidance for property owners and developers to ensure you navigate the intricacies of ADU construction successfully.

Renée White

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December 12, 2023
Table of content
    • It is possible to build an ADU before the main house in California, but there are many legal and practical complexities to doing so.
    • Different regions in California have different requirements for building ADUs, so you will have to check with local authorities before making your plans.
    • Remember that there are very strict rules around size for different types of ADUs, so you must familiarize yourself with the state legislation.
    • If you build an ADU without first obtaining a permit, you could face a number of consequences from fines to insurance problems to potential lawsuits.
    • We can help with planning, building, and selling/renting an ADU in Contra Costa County.

    Can I Build An ADU Before The Main House In California? Understanding Legal And Practical Aspects

    In California, you can build an ADU before the main house, subject to certain regulations. Recent changes in legislation, including AB 881 and SB9, have relaxed certain zoning restrictions, so there is more flexibility for property owners and developers. However, there are various considerations that impact practicality, including:

    • Size and setback regulations
    • Utility connections
    • Access
    • Construction logistics

    There would have to be a detailed plan for both properties ahead of time, and this would need to be approved by local government. As such, consultation with local authorities and a thorough understanding of the evolving ADU laws are absolutely essential.

    If you intend to undertake a project like this in Contra Costa County, our experienced team of real estate professionals can help. Whatever your plans, come to us for assistance with planning and constructing an ADU before the main property.


    Navigating Zoning And Land Use Regulations For An ADU In California

    Your ability to build an ADU before the main residence in California will be influenced by zoning restrictions, particularly relating to land use policies in different cities. Local ordinances dictate rules about things like:

    • Setbacks
    • Size limitations
    • Zoning classifications

    These can vary across municipalities. Recent legislative updates, like AB 881, have introduced easing to zoning restrictions, but it is still crucial to adhere to local regulations.

    When creating your project design, you will need to think about zoning classifications, setback requirements, and local land use policies. Consult local planning departments and keep abreast of zoning updates. If you remain compliant when planning your project, you should be able to get the necessary permits and navigate the intricate ADU construction laws in California successfully.

    Building An ADU Before The Main House In In Other Areas Of California

    We operate in Contra Costa, and recent changes to the laws mean you can now sell an ADU property as a condominium. This is just one among a raft of changes that is sure to shake up the housing market. With an increased demand for ADUs on land, there are likely to be more instances of people planning to build them on properties where the main dwelling hasn’t yet been constructed, so the need to build an ADU before the main house could increase in California.

    The regulations will inevitably vary between different regions, so it is important to be fully informed of where you stand in your locale. Let’s take a look at the considerations in Contra Costa, Los Angeles, and San Francisco to illustrate the variation between popular areas of the California real estate landscape.

    Can I Build An ADU Before The Main House In Contra Costa?

    Yes, you can build an ADU before the main house in Contra Costa. But doing so may make it more challenging to get approval for your planning application. You will need to create a detailed plan for the construction that illustrates that both the ADU and the proposed main residence will be fully compliant with local regulations. Your plans will be scrutinized, so they need to be perfect.

    Come to us for help with this. We are a team of real estate professionals with an extensive network in areas of finance, planning, and construction in Contra Costa County. No matter where you intend to build, we can help prepare for things like zoning and relevant legislation, and even other considerations like property taxes and more. Work with us to maximize your chances of success to build an ADU before the main house in Contra Costa.

    Can I Build An ADU Before The Main House In Los Angeles?

    Generally speaking, Los Angeles ADU ordinance allows ADU construction on residentially-zoned lots as long as there is an existing home already on the property. Thus, it is challenging to build an ADU before the main house in this particular part of California. But it is not impossible, particularly for developers, so you could still be successful with the right planning and preparation. Again, your plans must be fully compliant and ready to withstand intense scrutiny.

    As such, it is crucial to work with local planning departments and seek professional guidance on obtaining the necessary permits. You should also aim to work with trusted contractors and make allowances in your budget for unforeseen changes. With the necessary preparation, it is possible for housing developers to build an ADU before the main house in Los Angeles.

    Can I Build An ADU Before The Main House In San Francisco?

    There are strict zoning requirements in San Francisco, so the question of whether you can build an ADU before the main house depends on whether you can create a compliant design. It is more challenging to do so without the main property already in place, so you will need a good team at your disposal with knowledge of local requirements to create the planning for your project. But it is possible to construct the ADU first if you are able to get the permits to do it.

    Again, work with local experts and planning departments to make sure the plans you submit are fully compliant. It will not be a simple project, with intricate rules around open space requirements, size restrictions, and more. There may even be scope to explore the option of tiny homes for ambitious developers, but there are many considerations around this throughout California.

    California’s ADU Size And Comparison To Primary Residence: Design, Size Limits, And Strategic Planning

    In California, local municipalities are permitted to impose a maximum size limit on ADU projects, but this cannot be lower than 800 square feet. There is variation in this throughout the state, with many cities allowing ADU size up to 1,200 square feet, and height restrictions vary as well. When it comes to detached ADUs, the size of your build is not dependent on that of the main residence. If you are planning for an attached ADU, however, the size cannot exceed 50% of the square footage of the main residence.

    If you plan to build an ADU before the main house in California, an understanding of the size and zoning regulations is just the beginning. You also need to design for efficiency, so open-plan layouts are often preferred. This is a great way to make the best use of space whilst adhering to restrictions, whether you plan to sell or rent out your ADU.

    How Big Can My ADU Be In California? Sizing Guidelines And Tips

    Whether or not you plan to build an ADU before the main house in California, there are specific guidelines for size. Whilst these vary somewhat between different counties and municipalities, recent changes to legislation have relaxed the rules somewhat. Here are the key provisions:

    • Attached ADUs: The maximum size is typically 50% of the primary dwelling, up to a maximum of 1,200 square feet.
    • Detached ADUs: The maximum size imposed by cities cannot be less than 800 square feet, but it is often set at 1,200 square feet.
    • Converted ADUs: These don’t usually have any restrictions imposed on size.
    • JADUs: The maximum size limit is usually 500 square feet, and it must be contained within a single-family structure.

    Once you are aware of these size restrictions, as well as zoning requirements, you can aim to create a plan that makes maximum use of the allowable square footage. Always remember to check local ordinances carefully before creating a plan.

    Building And Permitting Process Before Your Main House For ADUs In California: From Application To Construction

    In order to secure permits to build an ADU before the main house in California, you will have to create a detailed plan for both constructions that adheres to all the local zoning and other building regulations. To achieve this, you will need to do the following:

    1. Familiarize yourself with local regulations.
    2. Consult with local planning departments and other professionals.
    3. Create and submit preliminary plans with the help of local experts.
    4. Attend public hearings (if required).
    5. Obtain the approvals from local planning departments and secure building permits.
    6. Oversee construction.

    The absence of the primary residence will mean that adherence to building codes and standards will be scrutinized during construction of your ADU. As such, you will need to be familiar with:

    • The California Residential Code (CRC)
    • Local building codes
    • Zoning ordinances
    • Fire safety standards
    • Energy efficiency standards
    • Plumbing/electrical codes
    • Accessibility requirements
    • Structural engineering standards
    • Permitting and inspections
    • Health and safety

    If you are able to keep on top of all these requirements, you may complete your project and have a very desirable property to sell in California.

    What Happens If I Build An ADU Without A Permit In California? Legal Consequences And Solutions

    If you proceed with building an ADU without obtaining a permit first, there are various consequences that you may face. First of all, you will be unable to get home insurance, which can lead to its own issues. But you may also be subject to fines from local authorities and potential lawsuits from tenants if you are renting your ADU and something goes wrong.

    It is known that there are many ADUs in California that were built without permits under the strict regulations. The recent relaxing of many rules makes it easier to get a permit, so it is advisable to seek approval even for existing constructions if they comply with the new regulations.

    Can I Build An ADU After The Main House In California?

    If you own a property in California with the necessary space to build a compliant ADU, and you have the budget to do so, you are in with a good chance of being able to build one. The recent updates to the legislation make it easier than ever before to get a permit, but there are still stringent requirements that you must meet to be approved.

    ADU Placement And Structure In California: Previous To The Main House

    When planning your building project with the intention of adding an ADU before constructing the main house in California, there are various places to build the accessory unit. For detached ones, you could convert an existing structure like a barn or standalone garage, or you could build one in the backyard. For attached ADUs, you could consider having one attached to the main house, above the garage, or in the basement. It all depends on local regulations, site characteristics, and your specific needs.

    One key consideration is structure. You need to have a strong understanding of foundation types and materials, so work with your contractors, as well as local planning authorities, when planning your ADU.


    Can You Put An ADU In Your Front Yard In California? Zoning And Aesthetic Considerations

    Generally speaking, due to zoning restrictions, ADUs cannot be built in front yards.There are rules in place to preserve neighborhood character and maintain an aesthetically-pleasing streetscape. Moreover, there are rules around setbacks and more, so you will need to consult with your local planning or building department for the exact rules for your locale.

    It’s important to bear in mind, however, that there has been a relaxing of rules relating to the front setback in California. If you are looking to build an ADU before the main house, check local ordinances to ascertain where you can and cannot erect the building.

    Frequently Asked Questions

    Can You Build An ADU Before The Main House In California?

    In theory, it is possible. But there are many legal and practical considerations that make it far more challenging than it is to build the ADU after the main house.

    Can I Build An ADU On My Property In California?

    If you own a property in California and have the space and budget to do so, you can build an ADU. But you will have to obtain a permit to do this, which means demonstrating that your plans align with local regulations and legislation.

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