7 Key Things to Consider Before Building an ADU in San Diego
Building an ADU (Accessory Dwelling Unit) in San Diego is one of the most effective ways to increase your property value, generate rental income, or create more livable space. But before you dive into the design or construction phase, there are several important factors to consider that can make or break your project. At Romex Design, we’ve helped homeowners across San Diego navigate the process with clarity and confidence. Here’s what you need to know before you build.
1. Understand What’s Allowed on Your Property
San Diego has made it easier than ever to build ADUs, but every property is different. Start by checking your zoning regulations, lot size, and existing structures. Some properties allow detached ADUs, while others only permit conversions of garages or interior space.
Tip: Romex Design can provide a feasibility assessment based on your parcel, saving you time and guesswork.
2. Know the Types of ADUs You Can Build
There are multiple types of ADUs in San Diego:
Detached ADU – A separate unit in your backyard
Attached ADU – Built as an extension of your home
Garage Conversion – Transforming an existing garage into livable space
Junior ADU (JADU) – A small unit (up to 500 sq ft) within the primary residence
Each comes with different guidelines and costs. Our team at Romex Design can help you determine which type best fits your property and goals.
3. Set a Realistic Budget
The cost of building an ADU in San Diego varies depending on size, finishes, utility hookups, and site prep. It’s not just construction—be sure to factor in design fees, permits, impact fees (if any), and potential landscaping.
Need help with financing? Romex Design can connect you with local financing partners who specialize in home construction loans and ADU-specific funding.
4. Check Setbacks and Height Restrictions
Even with relaxed ADU rules in San Diego, you’ll still need to follow setback, height, and lot coverage limits. These affect where your ADU can be placed and how large it can be.
Our expert team at Romex Design is experienced in navigating city code and can help you optimize your design to comply without sacrificing functionality.
5. Plan for Permitting
Getting permits in San Diego can be a process—but we make it easier. Romex Design prepares permit-ready plans and handles submittals, revisions, and coordination with the city. We know what local reviewers look for and how to avoid delays.
6. Think About Utilities and Access
Your ADU will need access to water, sewer, electricity, and potentially gas. Depending on your lot, extending these services can impact both cost and layout. You’ll also need to consider how your tenant (or family member) will access the unit—privacy and safety are key.
7. Choose the Right Design and Build Team
The design of your ADU should reflect your lifestyle, property layout, and long-term goals. At Romex Design, we take a tailored approach to every ADU in San Diego, offering architectural design, Title 24 reports, and builder referrals to ensure your project is seamless from start to finish.
Final Thoughts: Build Your San Diego ADU with Confidence
Building an ADU in San Diego is an exciting investment—but starting with the right information and support is essential. At Romex Design, we offer expert guidance, local knowledge, and design-forward solutions to help homeowners turn ideas into reality.
Ready to build your ADU in San Diego?
Let’s talk about your vision. Contact Romex Design today to schedule your free consultation.
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