Building an ADU in Southern California is a great idea, but you need to navigate the sometimes complex zoning laws and permitting requirements first.

1. Understand Local Zoning Laws: Each city and county in California has its own set of zoning laws for ADUs. In Los Angeles, for example, ADUs are allowed on most single-family lots, but other cities may have stricter regulations regarding setbacks and height limits.
   • Key Tip: Contact your local planning department early to verify the zoning laws for your specific property.
2. Permitting Process: You’ll need multiple permits before breaking ground—zoning permits, building permits, and potentially utility permits (for sewer, electrical, and water connections). In Los Angeles, a typical ADU permit can take anywhere from 4-6 months, so plan ahead.
   • Step-by-Step: Submit architectural drawings, a site plan, and other documentation, then wait for approval before beginning construction.
3. Avoid Setback Issues: In many cities, ADUs must comply with setback requirements—meaning they must be a certain distance away from property lines. This varies but is often 4-5 feet from side and rear property lines.
4. Parking Requirements: While some cities have reduced parking requirements (especially if your property is near public transit), others may still require an additional parking space for the ADU.
5. Utility Considerations: You’ll need to hook up the ADU to utilities, which requires coordination with local agencies. In some cases, this can be a significant cost, especially if the property needs upgraded electrical or water lines to handle the new load.