Only a portion of the beach is 'public' - the Queens Beach. Don't recall how many feet back it is though. The beaches are pretty narrow in some places so could be that some areas are all public. If you're sitting on your porch or balcony drinking you won't be likely to get a ticket or anything like that. San Pedro is a friendly, laid back place overall, but please be considerate and don't put people in danger of drunken golf cart driving.