Good common sense and zoning are mutually exclusive concepts. For the city of San Diego you go to the third floor of 1222 1rst street. For the county you go the intersection of Ruffin and Clairemont Mesa Blvd. Other incorporated areas have their own jurisdiction.
The key it not to assume that just because the property has the zoning that the project will work.It could technically work but has so many requirements that make it a nightmare.I would look at it as doing a feasibility study more that just checking zoning.
You still have to understand the setbacks required parking spaces, sewer availability etc. You might find that it is not worth the trouble of building your own.
It could be less expensive and you avoid many potential pitfalls by finding what you are looking for already built. But if you can’t find that, be very careful about the property you choose with the idea of building your granny flat
