Rules and Regulations Governing San Diego ADUs

June 30, 2021

As personal circumstances change through life and housing costs increase, it may be time to consider an accessory dwelling unit, or ADU. Sometimes called granny flats or in-law flats, these structures have great usefulness and creative potential. The key is finding a professional skilled in ADU design as well as the permit process to see your project through successfully from initial ideas to finished addition. In San Diego, however, you also must consider the rules and regulations that govern all construction projects, including ADUs.

ADU Design Must Consider Size Limit

California law requires that attached ADUs be no more than 50% of the main house square footage. However, detached ADUs can be as large as 1,200 square feet, no matter the size of the main building. A reputable professional ADU builder San Diego will know this and work with your initial ideas.

Interior Space

California law mandates specific ways an ADU's interior space should be used. Plans must include these elements:

  • Kitchen of 50 square feet
  • Living room/bedroom of 70 square feet minimum
  • Bathroom of 30 square feet minimum that includes a toilet, sink, and tub or shower stall
  • Hallways and closets

An experienced ADU builder San Diego is a great resource for fine-tuning your plans.

ADU Height Legalities

The general rule is that ADUs should not be taller than 16 feet. If they are positioned within a home, they can be as tall as the main unit. The good news is that if an ADU is shorter than 16 feet and smaller than 750 square feet, there should not be a problem obtaining a building permit. 

Power and Water

You can connect an ADU to your fuse box if there is space. If you plan to rent it, however, you should install a separate meter. California laws also govern water and sewage connections. The main house and ADU can share the same connection, but the ADU's sewer must connect downstream of the main structure.

Property Placement

California law requires that an ADU must be set at least four feet away from the existing property line, also called a setback of four feet. However, if you are converting an old garage or starting new construction in the exact same location of a previous structure, your ADU design need not be concerned with placement and setbacks.

Other Considerations

Other California regulations your ADU builder San Diego must consider include:

  • Building materials - To ensure ADUs meet quality expectations, California restricts wood shingles, single-piece composite, metal sheathing, and laminate. Windows need double panes.
  • Parking - In California, those converting garages do not have to replace the lost parking. No parking spot is required if a unit is within half a mile of public transportation or in a historic district.
  • Number of ADUs - California law governs the number of ADUs one property can have. Home owners can build one detached ADU and a smaller unit called a junior ADU.

Get Started Today on Your ADU Design

With so many regulations to consider, putting your ADU project in the hands of professionals is a smart move. Design Appruv not only designs your project, but we also streamline the permitting process and build the unit. We are licensed, experienced, and focused on surpassing our clients' expectations. to get started.