Building an ADU in San Diego: What You Need to Know

What is an ADU?

An Accessory Dwelling Unit (ADU) is a secondary housing unit built on the same property as a primary residence. Also known as granny flats, backyard cottages, or in-law suites, ADUs come in various forms, including converted garages, standalone structures, or additions to existing homes. These units typically feature a kitchen, bathroom, and living space, providing independent living quarters separate from the main house.

Here at GreatBuildz, a free service that connects homeowners in Los Angeles, Orange, San Diego and Ventura Counties with reliable ADU contractors, we speak to homeowners every day about the process of building an ADU in San Diego – read on to learn more.

Why Build an ADU in San Diego?

Building an ADU in San Diego offers several compelling benefits:

  • Housing Affordability: With skyrocketing housing prices and limited inventory, ADUs provide a more affordable housing option for both homeowners and renters.
  • Supplemental Income: Through rental income or hosting family members, the additional income stream from ADUs can help offset mortgage payments or contribute to savings.
  • Multigenerational Living Arrangements: ADUs allow families to accommodate aging parents or adult children while maintaining privacy and independence
  • Sustainable Urban Development: By utilizing existing infrastructure, ADUs reduce sprawl.

Building an ADU in San Diego: What You Need to Know 1

Navigating San Diego’s ADU Regulations

Key Zoning Laws and Requirements

In San Diego, ADUs are regulated by both state and local ordinances. California state law, specifically Assembly Bill 68 and Senate Bill 13, mandates that local jurisdictions allow for the development of ADUs on single-family residential properties. 

Key zoning laws and requirements in San Diego include:

  • Regulations related to property setbacks
  • Maximum unit size
  • Parking requirements
  • Design standards

Understanding the Permit Process in San Diego

The permit process in San Diego typically begins with submitting architectural plans and permit applications to the city’s Development Services Department.

Permit requirements may vary depending on factors such as the size and location of the ADU, as well as whether it is new construction or a conversion. Homeowners may need to obtain permits for building, electrical, plumbing, and mechanical work.

Once the necessary permits are obtained, construction can commence. Throughout the construction process, inspections may be required to ensure compliance with building codes and regulations.

Planning Building an ADU in San Diego

Building an ADU in San Diego bright exterior home

Design Considerations for Your ADU

Designing your ADU involves thoughtful consideration of factors such as space utilization, aesthetics, and functionality. Since ADUs come in various forms, tailoring the design to your specific needs and preferences is key.

Maximizing space efficiency is crucial, especially in smaller ADUs. Open floor plans, multifunctional furniture, and clever storage solutions can help optimize limited square footage. Additionally, incorporating plenty of natural light and ventilation enhances the livability of the space.

Considering the needs of potential occupants is also important during the design phase. Whether it’s accommodating elderly parents, adult children, or tenants, designing with accessibility and privacy in mind ensures a comfortable living environment for everyone.

Choosing Between Detached, Attached, and Garage Conversion ADUs

One of the first decisions to make when planning your ADU project is choosing the type of ADU that best suits your property and lifestyle. 

  • Detached ADUs, standalone structures located in the backyard, offer maximum privacy and flexibility but may require more space and investment.
  • Attached ADUs, integrated into the existing primary residence, can be more cost-effective and convenient, especially for homeowners seeking proximity to amenities and shared utilities. However, design considerations such as soundproofing and privacy partitions are essential to maintain separation between the main house and the ADU.
  • Garage conversion ADUs repurpose existing garage space into living quarters, making them a cost-effective option for homeowners with underutilized garages. While garage conversions can save on construction costs and time, structural modifications and parking considerations must be addressed.

The Financial Aspect of Building an ADU

Building an ADU SD green kitchen

Estimating Construction Costs

Estimating construction costs for an ADU project in San Diego requires careful assessment of various factors, including the size, type, and complexity of the unit, as well as local construction and labor costs. On average, ADU construction costs in San Diego can range between $300 to $500 per square foot. or more, depending on these factors.

Key cost components include:

  • Site preparation
  • Foundation work
  • Structural framing
  • Roofing
  • Plumbing
  • Electrical
  • HVAC systems
  • Interior finishes
  • Permits

Additionally, factors such as accessibility upgrades, landscaping, and utility connections may contribute to overall costs.

Exploring Financing Options for Your ADU Project

Financing an ADU project in San Diego can be accomplished through various means, depending on individual financial circumstances and preferences. Homeowners may consider the following financing options:

  • Cash Savings: Using personal savings or investments to fund the ADU project can eliminate the need for debt and interest payments.
  • Home Equity Loans or Lines of Credit: Borrowing against the equity in your primary residence through home equity loans or lines of credit allows homeowners to access funds for ADU construction while leveraging their property’s value.
  • Construction Loans: Construction loans provide short-term financing to cover the costs of building an ADU. Once construction is complete, the loan can be refinanced into a traditional mortgage or paid off with other financing.
  • ADU Financing Programs: Some municipalities offer financing programs specifically designed to support ADU construction. These programs may include low-interest loans, grants, or incentives to encourage ADU development and address housing affordability.
  • Rental Income: Generating rental income from the ADU can offset construction costs over time and contribute to long-term financial sustainability.

Maximizing Your ADU’s Potential

ADU SD Exterior design

Rental Income and Property Value Increase

Renting out the ADU can provide homeowners with a steady stream of passive income, helping to offset mortgage payments, property taxes, and maintenance costs. Moreover, ADUs can significantly increase the overall property value. The additional living space and rental income potential make properties with ADUs more attractive to buyers, resulting in higher resale values. Well-designed and professionally constructed ADUs that comply with zoning regulations and building codes can yield substantial returns on investment, making them a valuable asset for homeowners in San Diego.

ADUs as a Solution for Housing Family Members

In addition to generating rental income, ADUs offer a practical solution for housing family members. Whether accommodating aging parents, adult children, or relatives, ADUs provide a comfortable and independent living space while maintaining proximity to the main residence. This arrangement promotes multigenerational living and strengthens family bonds by allowing loved ones to live nearby while preserving privacy and autonomy.

ADUs can also serve as transitional housing for family members during life changes such as downsizing, job relocation, or divorce. Instead of facing the challenges of finding suitable housing in a competitive market, family members can reside in the ADU temporarily or long-term, providing stability and support during times of transition.

To be matched with pre-vetted, trusted ADU contractors who can help bring your vision to life safely, building an ADU in San Diego on time, and on budget, contact GreatBuildz today at (818.317.3567) or visit our website for more information.

Hi, we're Paul and Jon - Co-Founders of GreatBuildz. We believe everyone deserves to find a great contractor, have a stress-free renovation, and enjoy their beautiful new space. There are so many contractors out there and it's often hard to tell the good from the bad... until it's too late. We started our company to help simplify your contractor search and help you have a stress-free renovation experience. We're always available to help, no matter where you are in the process. Click here to learn more about our story.
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