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Orinda’s Requirements For Building An ADU

If you are considering building an ADU in Orinda, be aware that there are various rules and regulations, many of which have changed recently for all of California. Discover the Orinda requirements for building an ADU in this detailed blog post. The legislation that governs processes like getting a permit and moving forward with construction need to be understood, with considerations like zoning regulations and size guidance. We walk you through everything in this post.

Whether you’re a seasoned property investor or developer, or merely a homeowner exploring options, these evolving laws about Orinda’s ADU requirements need to be comprehended. Let us be your guide and get ahead of the legalities.

a luxurious adu by a pool for adu builder orinda
Renee White
Written by Renée White
  / February 26, 2024

Renée White is a top-producing real estate broker with over 20 years of experience and an annual average of 200 sales. Clients are drawn to Renée for her deep knowledge of the local Contra Costa market.

Table of content
    • Orinda’s ADU ordinance tells you everything you can and can’t do in the planning, permitting, construction, and use of accessory dwelling units.
    • The state of California has recently updated its legislation, impacting ADU requirements in Orinda.
    • Orinda ADUs are currently limited to 1,200 square feet and 16 feet tall.
    • An ADU is required to have its own kitchen and bathroom to function independently as a separate dwelling from the main residence.
    • We are one of Contra Costa’s leading real estate agencies and can answer your questions on ADU legislation, including selling/renting.

    What Are Orinda’s ADU Requirements?

    If you haven’t heard of accessory dwelling units (ADUs), you have probably heard of their other aliases, including:

    • Guest houses
    • Granny flats
    • Secondary units

    It’s important to have a strong understanding of Orinda’s ADU requirements if you plan to bring one onto the Contra Costa housing market. As an ADU builder in Orinda, you can design these dwellings to be attached to your main residence, detached as a new construction, or a conversion of an existing structure like a standalone garage. To build an ADU in Orinda, you must ensure that your design:

    • Complies with zoning regulations
    • Conforms to setback and size requirements
    • Meets local legislation for things like utilities and parking
    • Is approved by the local planning authority

    2023 saw sweeping changes to California legislation regarding the construction of ADUs, directly impacting the regulations in Orinda. The updates to the laws enabled people to sell or rent ADUs as condos, enforced greater transparency on the 60-day rule for decisions on permits, and eased restrictions around ADU size and front setbacks. Essentially, these new Assembly and Senate Bills make the securing of a permit for an ADU far less prohibitive. Some regions have used flexibility and loopholes to give their own spin on the guidelines, so here are some specifics for Orinda:

    • Attached ADUs: These can have no more than 50% of the square footage of the main residence, capped at a maximum of 1,200 square feet. The height cannot exceed 25 feet, or that of the main residence – whichever is the lowest.
    • Detached ADUs: A detached ADU on a single-family lot can be no larger than 1,200 square feet, and no taller than 16 feet. There are slightly different rules for multi-family lots.
    • Converted ADUs: These have no restrictions, as the structure already exists.

    If you intend to be an ADU builder in Orinda with the aim of renting or selling the construct as its own dwelling, be aware that Orinda property taxes will apply. Let’s move on to explore some more details about ADUs in Orinda.

    Who Do You Need To Be?

    Essentially, to comply with Orinda ADU requirements, you must be a property owner in the city. You must also have the capital or appropriate funding as well as sufficient space on your lot to build a compliant ADU. In a nutshell, if you own your lot and are able to meet the requirements listed in the current ADU legislation, you can go ahead and build an ADU in Orinda.

    What Income Do You Need?

    The amount of income required to be an ADU builder in Orinda depends on the specifics of your project. There are fees to pay in order to obtain a permit, and the cost of designing and planning your ADU depends on who does the work and the size/complexity of your plans. And, of course, the construction phase costs money as well. As a general guideline, you can typically expect to spend between $50,000 and $300,000 on an ADU in Orinda, which we could then help you rent or sell to get a return on your investment.

    Where Do You Need To Be?

    To build an ADU in Orinda, you need to own a property within the city limits. The rules are similar throughout Contra Costa County, but elsewhere in California you may encounter different ordinances around the construction of ADUs. You will need to submit an application to your local authority to acquire a permit.

    What Actually Are ADU Builder Laws In Orinda Exactly?

    Orinda’s ADU builder laws are a set of legislation governing the construction and use of accessory dwelling units. These constructions come in many shapes and sizes. The laws around them have long been criticized as overly restrictive and vague, and campaigns for reform eventually led to Assembly Bills 976, 1033, and 2221 to change the ADU landscape.

    With the new legislation, there is greater freedom around building ADUs in Orinda and elsewhere in California. This is a welcome change for existing homeowners and prospective buyers in this sought-after housing market.

    What Is Orinda’s ADU Builder Ordinance?

    Orinda’s ADU ordinance is the specific set of guidelines and instructions for designing, building, and using accessory dwelling units in the city. Typically, ADU ordinance instructs on rules around zoning, maximum sizes, setbacks, and whether or not properties can be sold as separate dwellings.

    Compatibility with the existing neighborhood is important, so the latest regulatory changes seek to enable more streamlined approval of ADUs whilst preserving the character of local communities. This state-mandated legislation aims to address prominent issues with housing shortages in the Golden State. 

    What Are Orinda’s Local Ordinances For ADU Requirements?

    As experienced, respected real estate agents in Orinda, we are always up on the latest developments in the city. The recent ADU changes have shaken up the housing market here, so let’s look at some key legislative updates:

    • AB 157: This allows for ADUs with no requirements for providing off-street parking, eliminating one of the most common barriers to approval.
    • AB 916: Making provisions for financial incentives for homeowners to build ADUs on their property.
    • SB 897: Modifying the previous restrictions on ADU size, allowing a maximum limit of 1,500 square feet. Orinda’s maximum currently stands at 1,200 square feet, so watch for potential changes.
    • AB 2221: A bill aimed at streamlining the ADU permitting process and enabling the creation of JADUs with fewer requirements and regulations.

    To navigate all this, it can be helpful to have a team of experienced experts at your side. We specialize in helping clients with property transactions of all types, and can advise on certain factors of planning, building, and selling/renting ADUs in Orinda. Explore our customer reviews to see how we have helped hundreds of buyers and sellers all over Contra Costa.

    blueprint for a construction for adu builder orinda

    What Qualifies As An ADU In Orinda?

    Orinda’s ADU requirements define an accessory dwelling unit as a secondary residential unit on an existing lot that is complete and independent of the main dwelling. It must have all the necessary utilities built in, including a kitchen and bathroom, and ADUs are subject to certain zoning and building restrictions.

    The Orinda market for ADUs has seen numerous recent legislative changes, including:

    • AB 68: Allowing for more than one ADU on a single-family lot, whilst also easing the lot size requirements.
    • SB 13: Addressing nuisance barriers to ADU development like prohibitive construction fees and restrictive parking requirements.
    • AB 881: Modifying several construction-related issues like setback standards and height limitations.

    These requirements are a key consideration for ADU builders in Orinda. Keep up-to-date on all you need to know and your project should go ahead smoothly. We can assist with this, as we have a finger on the pulse of all the latest developments for real estate in Orinda.

    The Orinda ADU And Zoning Laws

    Orinda’s zoning regulations have changed within the new Contra Costa ADU rules. You can now add 2 new units to your lot if you have the necessary space. AB 68 compels municipalities to approve ADU plans up to 1,200 square feet and JADUs up to 500 square feet. For multi-family units, plans can include multiple ADUs attached to existing structures plus up to 2 detached ADUs on the lot. These changes pave the way for some more expansive and sophisticated plans for developers and homeowners.


    The maximum ADU size cannot be less than 800 square feet and 16 feet in height, and a 4-foot rear and side yard setback is permitted. For ADU builders in Orinda, the maximum size is 1,200 square feet, though this could be increased. Contact us if you need any advice regarding the prospect of renting or selling an ADU in Orinda or elsewhere in Contra Costa. We have a wealth of experience and expertise in helping sellers and buyers in Orinda with a wide range of property types, so we can help you secure the best possible deal.

    How To Build An ADU In Orinda Following All The Requirements

    The process of obtaining a permit to be an ADU builder in Orinda has now been simplified. The relaxed restrictions around size and zoning have effectively removed many of the common barriers to approval, which previously included front setbacks and off-street parking. Essentially, it is now much simpler to create a compliant plan for an ADU on your lot.

    It is wise to work with local planning departments so that you have a clear idea of what you need to do for approval. This will increase your chances of success. Once you have completed your plan and submitted your application, there is still a 60-day window for approval or denial. But, under the new rules, the City of Orinda is required to be very transparent about the process, and they must provide detailed reasons if they refuse your application, including recommendations for a successful reapplication.

    Another key consideration is your budget. You need to be able to cover:

    • The fees for obtaining your permit
    • The costs of developing a design
    • The cost of construction

    The actual amount of capital required depends on your plans. Some regions offer financial incentives as there is a strong desire for people to build ADUs in California. Explore this with the City of Orinda – there are no schemes at the time of writing, but there may be plans to introduce some in the future. There are also various finance options available to help you proceed with this investment in your property. If you can bring your plan to fruition, you could see some big returns if you rent or sell your ADU down the line.

    construction materials for adu builder orinda

    Reduced Parking Requirements For ADUs

    The City of Orinda can no longer mandate for off-street parking for prefabricated ADUs that are:

    • Situated in historic districts
    • Within a half-mile of public transportation
    • An integral part of the main house or a pre-existing ancillary structure

    Parking restrictions have been a notorious barrier for prospective ADU builders in Orinda. The easing of these requirements make it far simpler to create plans that comply with all the necessary ADU requirements in Orinda. This is already making waves in the Orinda housing market, so there is hope that this will make a difference in the housing shortage.

    Frequently Asked Questions

    What Are The Requirements To Build An ADU In Orinda?

    In Orinda, an ADU must be a secondary, completely independent dwelling on an existing residential lot. At present, they can be up to 1,200 square feet in size, and the minimum rear and side setback is 4 feet.

    What Are Orinda’s Local Ordinances For ADU Requirements?

    Orinda’s local ordinances are the mandatory ADU requirements that instruct on the planning, permitting, building, and use of ADUs in the city. They are very detailed so it is important to familiarize yourself with the requirements.

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