Am I allowed to build an ADU?

In almost all cases, the answer is yes! The best way to find out is to use the County’s Web GIS Tool to find out more information about your parcel. This online mapping tool provided by the county allows you to look up important information about your property using an address or APN, such as lot size, what you can build, and whether there are any additional restrictions. With some technical exceptions, ADU development is allowed wherever residential development exists or is permitted. Alternatively, you can contact the county’s building and planning department to speak with a planner.