How Big Can an ADU Be in California? Size Limits and Design Tips
The demand for additional living spaces continues to grow. As a result, many California homeowners are turning to Accessory Dwelling Units (ADUs) as a solution. However, before you opt to build an ADU, you need to understand the ADU size limits in California. In this guide, we’ll discuss how big an ADU can be in California. By knowing the size limits and design options when constructing an ADU, you can ensure your project meets state regulations while maximizing your property’s potential. Understanding California’s ADU Size Regulations Recently, a client of mine, Sarah, approached me with a vision to transform a portion of her backyard into a comfortable living area for her elderly parents. She had heard about ADUs and was excited about the possibility. However, before diving into the planning process, I ran Sarah through the different factors she needed to keep in mind, including the size limits. She wanted the space to be large enough to accommodate her parents’ needs while still complying with state regulations. Ultimately, we carefully planned out the size and design options, which not only gave her peace of mind but also sparked creative ideas on how to make the most of the space she had available. As mentioned earlier, California has established specific guidelines for ADU sizes to maintain the character of neighborhoods. These limitations also ensure the new units blend seamlessly with existing homes. The size of an ADU can vary based on several factors, including the type of ADU, the size of your lot, and local city ordinances. Maximum Size Limits for ADUs The maximum size an ADU can have in California is typically capped at 1,200 square feet. However, there are additional factors you need to consider depending on the type of ADU: Detached ADUs: For a standalone structure, a detached ADU can be up to 1,200 square feet, regardless of the size of the existing dwelling. Attached ADUs: If the ADU is attached to the main house, its size is generally limited to 50% of the square footage of the existing home, with a maximum of 1,200 square feet. For example, if your main home is 2,000 square feet, your attached ADU can be up to 1,000 square feet. Junior ADUs (JADUs): A JADU is a smaller kind of ADU that can be up to 500 square feet. Moreover, it’s created by converting an existing bedroom or other space within the main home. Design Options to Maximize Your ADU Space To design an ADU within these size constraints, you need to carefully plan out how to balance both space and functionality. Here are some design options for you to consider: Open Floor Plans: Embrace an open floor plan to make the ADU feel more spacious. By minimizing interior walls, you can create a more versatile and inviting living area. Multi-Functional Spaces: Consider designing rooms that serve multiple purposes. For instance, a dining area could double as a workspace, or a living room could convert into a guest sleeping area. Vertical Expansion: If horizontal space is limited, you can utilize vertical space with higher ceilings or loft areas. This approach can make the ADU feel larger than it is. Outdoor Extensions: Integrate outdoor spaces like patios or decks to extend the living area of your ADU. These areas can serve as additional living or dining spaces, making the overall unit more functional. Local Variations and What You Need to Know While California provides general guidelines, local city ordinances may impose additional restrictions or allowances on ADU sizes. Here’s what you need to consider: City and County Ordinances Each city and county in California can adopt its own ADU ordinances, which may differ from the state’s baseline requirements. For instance, some cities may impose a lower maximum square footage limit than the state allows, particularly in areas that prioritize maintaining neighborhood character. Conversely, others might allow slightly larger ADUs or more relaxed setback requirements, especially in areas with housing shortages. Historic Districts and Special Zones If your property is located in a historic district or a special zoning area like a coastal zone, additional regulations may apply. In historic districts, for example, the design and materials of your ADU may need to match the architectural style of the existing structures in the area. Additionally, in coastal zones, you may face restrictions related to environmental protection or public access that could affect the placement and size of your ADU. Incentives and Exceptions On the other hand, some cities offer incentives for ADU construction that could benefit your project. For example, in certain urban areas, local governments may allow larger ADUs or waive parking requirements if the ADU is within a specified distance of public transportation. These incentives are designed to encourage the development of ADUs, which would address housing shortages and promote sustainable urban living. FAQs 1. Can I build more than one ADU on my property? Yes, in some cases, you can build both an ADU and a Junior ADU (JADU) on the same property, depending on local regulations. 2. Do I need a permit to build an ADU in California? Yes, you must get a permit to construct an ADU in California, and the process includes design approval and inspections. 3. Can I convert my garage into an ADU? Yes, you can convert a garage into an ADU. In fact, it’s often more straightforward since the structure already exists. Conclusion In summary, the size of an ADU in California depends on the type of unit and local regulations. But typically, it’s a maximum of 1,200 square feet. Understanding these limits and exploring smart design options will help you make the most of your ADU project. If you’re considering adding an ADU to your property but aren’t sure where to start, contact our experts at GoldenADU at 213-693-2405 for a free consultation. We can guide you through every step, from design to construction, ensuring your ADU meets all state and local requirements.