How Big Can an ADU Be in California?

When planning to build an Accessory Dwelling Unit (ADU) in California, one of the most common questions homeowners ask is: how big can it be? The answer depends on the location, zoning regulations, and the type of ADU you’re building. Thankfully, recent legislation has made it easier than ever to build sizable and functional ADUs.

California state law now allows ADUs up to 1,200 square feet, regardless of the size of the primary residence. This is a significant change that supports the growing need for housing and flexibility for homeowners. Additionally, local jurisdictions may allow even larger units in certain cases or impose more specific requirements.

There are also distinctions between attached and detached ADUs. Detached ADUs, which are standalone units, often have more flexibility in terms of layout and size. Attached ADUs must be integrated into the footprint of the existing structure and may be limited to 50% of the size of the primary residence. For example, if your home is 2,000 square feet, your attached ADU could be up to 1,000 square feet.

Other considerations include setbacks (distance from property lines), maximum lot coverage, and height limits. For homeowners in the Los Angeles area, KIND Construction helps navigate these complexities with ease. We work closely with city planning departments to ensure your project complies with all local ordinances and maximizes the use of your available space.

Whether you're building for family, guests, or rental income, we design ADUs that are spacious, stylish, and optimized for modern living. From floor plan design to final finishes, KIND Construction ensures your ADU fits seamlessly into your property while adding long-term value.