Everything You Need to Know About ADUs in San Diego
Accessory Dwelling Units are transforming San Diego properties. Learn about types, permitting, zoning, costs, and how we can help you build your perfect ADU.
What is an ADU?
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a single-family residential lot. Also known as granny flats, in-law suites, backyard cottages, or casitas, ADUs provide independent living spaces with their own kitchen, bathroom, and sleeping area.
California has passed landmark legislation making it easier than ever to build ADUs, and San Diego has embraced these changes to address housing needs while giving homeowners new opportunities for income and flexibility.
Did You Know?
San Diego issued over 2,500 ADU permits in 2023 alone - more than any other California city outside Los Angeles.
Types of ADUs
Choose the ADU type that best fits your property, budget, and goals.
A standalone structure separate from the main house, typically in the backyard.
An addition built onto the existing home, sharing at least one wall.
Converting an existing garage into a livable dwelling unit.
A smaller unit within the existing home footprint, often a converted bedroom.
Benefits of Adding an ADU
Rental Income
Generate $1,500-$3,000+ monthly rental income in San Diego
Multi-Generational Living
Keep family close while maintaining privacy
Property Value
Increase your home value by 20-30%
Flexibility
Home office, guest house, or Airbnb rental
How ADU Permitting Works in San Diego
We handle the entire permitting process for you. Here's what to expect.
Site Assessment
We evaluate your property to determine the best ADU type, placement, and design options.
Design & Plans
Our architects create detailed plans that comply with San Diego building codes and zoning requirements.
Permit Application
We submit your plans to the City of San Diego for review and handle all required documentation.
City Review
The city reviews plans for zoning, building codes, fire safety, and utility connections.
Permit Approval
Once approved, you receive building permits and we can begin construction.
Construction & Inspections
We build your ADU with regular city inspections at each phase (foundation, framing, electrical, plumbing, final).
San Diego ADU Zoning Rules
Understanding zoning requirements is crucial for ADU planning. Here are the key regulations.
Setback Requirements
Detached ADUs typically require 4ft side and rear setbacks. Garage conversions may have no setback requirements.
Height Limits
ADUs are generally limited to 16ft for detached units, though two-story ADUs up to 18ft may be permitted in some zones.
Lot Coverage
San Diego allows ADUs even if they exceed typical lot coverage limits, as long as the ADU is under 800 sq ft.
Owner Occupancy
As of 2020, owner-occupancy requirements are suspended for ADUs permitted before 2025.
Frequently Asked Questions
ADU costs typically range from $150,000 to $350,000+ depending on size, finishes, and site conditions. Garage conversions start around $100,000. We provide detailed estimates during our free consultation.
In most cases, no. California law eliminates parking requirements for ADUs within half a mile of public transit, in historic districts, or when part of an existing structure. San Diego has adopted these state-wide exemptions.
Most single-family and multi-family residential properties in San Diego can have an ADU. Some restrictions apply in certain zones or for properties with HOA covenants. We assess eligibility during our free consultation.
From design to move-in ready, expect 8-14 months total. This includes 2-4 weeks for design, 4-8 weeks for permits, and 4-6 months for construction. We work to minimize delays at every stage.
San Diego allows short-term rentals in ADUs, but regulations vary by zone. Some areas require a short-term rental permit and have occupancy limits. We can help you understand the rules for your property.
ADUs need connections for electricity, water, sewer, and typically gas. In many cases, ADUs can connect to existing utilities. Separate meters may be required or optional depending on your rental plans.
Ready to Build Your ADU?
Get a free consultation and find out if your property is eligible. Our team handles everything from design to permits to construction.
Disclaimer: The information on this page is for general guidance only and may not reflect the most current California or local ADU regulations. Zoning rules, setback requirements, utility rules, and permit processes can change. Always confirm requirements with your local city or county building department and consult with a licensed design professional before starting any project. Modern Construx is not liable for decisions made based solely on this information.