As was mentioned, some areas of San Francisco have Home Owner's Associations....and most of them are obsolete having been made in the early 1900s and saying things like no Blacks or Chinese. Many of them have a fee of $100-$300 or so a year and the money is used to pay for the gardening of the common areas in the neighborhood (and that is why they look so good.)
Unfortunately, I do not know Berkeley but I can guess that the rules are probably the same. As for the downstairs with a kitchenette, you need to ask the Listing Agent if it was done with permits? If not, was an attempt made to Grandfather it in? And the same agent can tell you what will happen if you are caught with an illegal in-law. The rules are different for each city.
Good luck in your search! I know there are many great agents for Berkeley and the East Bay. Please contact me if you wish. I welcome your questions or if you want to look in San Francisco.