Legal Question in Real Estate Law in California

You don't need a contractor's license if you do not make any improvements to the houses that require permits or would require a contractor's license if you were doing the work for hire, or if you use a licensed contractor for such improvements. The only exception is you can obtain permits and do the work as an owner-builder if you live in the house for 12 months prior to completion of the work, and you only do two houses in any three year period. That's not a very useful exemption for flipping houses. So if you want to do the work as an owner-builder instead of working with a contractor, eventually you will want a contractor's license.

As for a real estate license, I think that would be very useful. I have never flipped houses but I did buy and sell rental properties. I always did my own work when I bought, because I had a relative who could be my broker of record to take the commission cut for me. Had I not had that, I definitely would have wanted a license to save 2.5-3% on my purchases. On sales, I always used an active agent. They always earned their commission by getting me the best price and handling all the requirements that the law puts on a seller. Even if I had my license, unless I had decided to be an active broker, I would have used someone who was.