A Comprehensive Guide to ADU Regulations in San Diego

 

Setting up an ADU in San Diego, or an Accessory Dwelling Unit, involves several key requirements:

  1. Zoning and Permits: Ensure your property is zoned for an ADU and secure necessary building permits.
  2. Size and Design Constraints: Adhere to the maximum size limits (1,200 sqft for detached units) and ensure design compatibility with your primary residence.
  3. Setback Regulations: Follow side and rear setback rules, typically zero for single-story units, while two-story units may require 4′ setbacks.
  4. Parking Requirements: Parking usually isn’t required unless your property is within specific coastal zones.
  5. Additional Considerations: Consider all additional local regulations like landscaping and digital submissions.

As San Diego continues to grapple with a housing crisis, exploring opportunities like building ADUs is increasingly appealing to homeowners. These small, self-contained living spaces not only offer additional rental income or family accommodation but also help address the city’s housing shortage. By becoming a crucial housing solution, ADUs provide flexibility for multigenerational living, improve property value, and contribute to community efforts toward sustainable development.

I’m Michael Kootchick, a seasoned real estate developer involved in the ADU sector. With my experience in housing projects, I’m here to guide you through the requirements for setting up an adu in san diego smoothly and effectively.

Infographic detailing ADU requirements in San Diego, showcasing zoning laws, maximum size, setback specifications, parking regulations, and additional considerations - requirements for setting up an adu in san diego infographic infographic-line-5-steps-colors

Requirements for Setting Up an ADU in San Diego

Setting up an ADU in San Diego requires navigating several important steps and regulations. Let’s break down the essentials so you can confidently move forward with your project.

Zoning and Eligibility

Residential Zoning:
First, check if your property is zoned for residential use. This is crucial because San Diego allows ADUs on lots with existing or proposed single-family homes. For multifamily properties, the rules are more flexible, permitting additional ADUs based on the number of existing units.

Single-Family Lots:
On single-family lots, you can add one ADU and one Junior ADU (JADU). Ensure that your lot complies with these zoning requirements to avoid any legal hiccups.

Multifamily Properties:
If you own a multifamily property, you’re in luck. You can typically add multiple ADUs, up to 25% of the existing units. This offers a great opportunity to expand living space and increase rental income.

Permit Process and Fees

Building Permits:
You’ll need a building permit from the City of San Diego. It’s essential to prepare thoroughly, as the process involves submitting detailed plans that align with local building codes and regulations.

Plan Check Fees:
When you apply for a permit, you’ll encounter plan check fees. These fees cover the cost of reviewing your plans to ensure compliance with all applicable standards. Fees can vary, but expect to pay between $1,500 and $2,500. This step is vital to ensure your project moves forward without delays.

Coastal Permits:
If your property is in the coastal zone, additional permits are necessary. The process for obtaining a coastal development permit (CDP) in San Diego has been streamlined, but it still requires careful attention to detail. Make sure your plans meet coastal regulations to avoid complications.

Size Limits, Setbacks, and Parking

Size Limits:
ADU size is a key consideration. Detached ADUs can be up to 1,200 square feet, while attached units are limited to 50% of the primary dwelling’s square footage or 1,200 square feet, whichever is less, but not less than 800 square feet.

Setbacks:
Setbacks are the required distances between your ADU and property lines. In San Diego, ADUs must comply with front and exterior side yard setbacks. A minimum side and rear setback of 4 feet is typical, although state law allows for some flexibility if space is limited.

Parking:
Parking requirements can be a concern, but San Diego has relaxed rules for ADUs. Generally, no parking is required if your property is near public transit or if the ADU is a conversion from an existing space. However, specific coastal zones might have different rules, so always double-check.

By understanding these requirements for setting up an ADU in San Diego, you can avoid common pitfalls and ensure a smoother process. Whether you’re adding an ADU to a single-family lot or a multifamily property, following these guidelines will help you create a valuable and compliant living space.

ADU Size and Design Constraints

When planning to build an Accessory Dwelling Unit (ADU) in San Diego, understanding size and design constraints is crucial. Let’s explore the key considerations for both detached and attached ADUs.

Detached ADUs

Maximum Size and Lot Coverage:
In San Diego, a detached ADU can be as large as 1,200 square feet. Notably, ADUs up to 800 square feet are exempt from lot coverage requirements. This means that even if your property is maxed out on lot coverage, you can still build a smaller ADU without additional zoning headaches.

Height Limits:
For height, detached ADUs can be at least 16 feet high with zero setbacks on the side and rear. If you want to build higher, you can go up to the maximum height allowed by the zoning laws, typically between 24 and 30 feet. However, taller structures need to observe a 4-foot setback from the side and rear property lines when adjacent to other residential premises.

Attached ADUs

Size Limitations:
Attached ADUs have a slightly different set of rules. They can be up to 50% of the size of the main house, with a cap at 1,200 square feet. This ensures that the ADU remains a secondary structure to the primary dwelling, maintaining the residential character of the neighborhood.

Design Flexibility:
One advantage of attached ADUs is the flexibility in design. You can convert existing spaces like garages or basements into ADUs, making them a cost-effective option. Plus, converting these spaces often means you can bypass some of the lot coverage and setback constraints that apply to new detached structures.

ADU Design Options - requirements for setting up an adu in san diego

By understanding these size and design constraints, you can better plan your ADU project. Whether opting for a detached or attached unit, these guidelines ensure your ADU is both functional and compliant with San Diego’s regulations.

Setback and Building Separation Requirements

When planning an ADU in San Diego, understanding setback and building separation requirements is key to ensuring your project is compliant and safe.

Setback Details

0′ Side/Rear Setbacks:
For ADUs up to 16 feet in height, you can build right up to the property line on the side and rear. This zero setback allowance provides more flexibility in placing your ADU, especially on smaller lots. But, it’s important to note that this is only an option if your ADU is a single story and under the height limit.

4′ Preferred for Two-Story ADUs:
If your ADU exceeds 16 feet in height or is a two-story structure, you must maintain a 4-foot setback from the side and rear property lines. This requirement is particularly important when your property abuts another residentially zoned area. The increased setback helps maintain privacy and reduces the impact on neighboring properties.

Building Separation

6 Feet Minimum Separation:
San Diego regulations require a minimum of 6 feet of separation between the ADU and any other structures on the same property. This distance helps ensure fire safety and provides enough space for maintenance and access.

Fire-Rated Materials:
If your ADU is closer than 5 feet to a property line, the building code mandates the use of fire-rated materials. This requirement can increase construction costs but is crucial for safety, particularly in fire-prone areas like San Diego. Using these materials helps protect both your investment and the surrounding community during the fire season.

Understanding setback and building separation requirements is essential for safe and compliant ADU construction. - requirements for setting up an adu in san diego infographic checklist-light-beige

 

Parking and Additional Requirements

Parking Regulations

When setting up an ADU in San Diego, parking requirements are often a major concern for homeowners. However, the city has made it easier by waiving most parking requirements for ADUs. This means no parking is required for ADUs located outside the Coastal Overlay Zone.

Exceptions in Coastal Zones:
If your property is within the Coastal Overlay Zone, parking rules are a bit different. Generally, no parking is required unless you’re in the Beach Impact Area of the Parking Impact Overlay Zone and outside a sustainable development area. In this case, you need one off-street parking space unless:

  • The ADU is 500 square feet or less.
  • The property is a historical district.
  • The ADU is attached to the primary dwelling or accessory structure.
  • The property is in a residential permit parking district.
  • A car share vehicle is within one block of the property.

Additional Considerations

Landscaping:
If you’re adding two or more ADUs or JADUs on your property, you must provide two trees for every 5,000 square feet of lot area. At least one tree must be planted on the premises. Choose trees according to the Landscape Standards of the Land Development Manual and the City’s Street Tree Selection Guide.

Exterior Design:
While designing your ADU, consider the exterior aesthetic to match or complement the primary dwelling. This can improve the overall appearance and value of your property.

Digital Submissions:
San Diego allows for digital submission of ADU applications, simplifying the process significantly. This means you can submit your documents online without needing to visit city offices, saving you time and effort.

 

Frequently Asked Questions about ADU Regulations

What are the new laws for ADUs in San Diego?

Recent changes in California state laws have made it easier to build Accessory Dwelling Units (ADUs). Assembly Bill 68 (AB 68) is a key law that prevents local governments from imposing overly strict rules on ADUs. It ensures that homeowners can build ADUs without worrying about minimum lot sizes or excessive setbacks. This law also allows ADUs to be attached to existing structures like garages or storage areas.

Senate Bill 1211 (SB1211), effective January 2025, will allow multifamily property owners to build as many ADUs as there are existing units, up to a maximum of eight detached ADUs. This is a big change aimed at increasing housing options.

Junior Accessory Dwelling Units (JADUs) are also part of the new regulations. JADUs must be converted from existing space within the primary residence and require owner occupancy. They offer a smaller, more affordable option for adding living space.

How much does an ADU permit cost in San Diego?

The cost of an ADU permit in San Diego can vary depending on the size and complexity of the project. Plan check fees are typically between $1,500 and $2,500. This fee covers the city’s review of your plans to ensure they meet all regulations.

Once your plans are approved, you’ll encounter additional fees. These might include building permit fees, which are similar in cost to the plan check fees, and school impact fees, which vary by district. There may also be small fees for sewer and water meter reviews.

Can you build a two-story ADU in San Diego?

Yes, you can build a two-story ADU in San Diego. The height limit for a detached ADU is up to 24 feet, allowing for two stories. However, it’s important to note that fire codes may require special materials or fire-rated construction if the ADU is closer than 10 feet to another structure.

While designing a two-story ADU, ensure it complies with all setback requirements and consider how it will fit with the existing structures on your property. Two-story ADUs can offer more living space without expanding the footprint, making them a popular choice in areas with limited lot space.

 

The OneStop ADU Difference

Building an ADU in San Diego can be a complex process, but OneStop ADU is here to make it easier. Our comprehensive services cover everything from initial design to final permit processing, ensuring a smooth experience from start to finish.

We understand the importance of time and cost efficiency. That’s why we offer pre-designed plans that can save you both time and money. By using these plans, you can skip some of the lengthy design phases and move quickly to the construction stage. Plus, our experts handle all the permit paperwork and interactions with local authorities, so you don’t have to worry about the details.

Our team is well-versed in San Diego’s ADU regulations, including zoning, size limits, and setback requirements. We ensure your project complies with all local codes while maximizing space, natural light, and energy efficiency. Whether you’re considering a detached or attached ADU, we’ll guide you through the process with ease.

Choosing OneStop ADU means choosing a partner who understands your needs and works diligently to make your ADU dream a reality. Ready to get started? Contact us today for a free property analysis and estimate. Let’s transform your space into a valuable asset.

 

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