Permission to convert garage into studio

[Jenny Ha My]

Hello,

We intend to buy a house in Hayward, California. This house has a 2-car garage which was converted into studio more than 20 years ago (the seller also shows us the document of permission to convert). However, when I talked to a friend who lives near by, he said that Hayward city has law which requires all houses in Hayward must have garage. In my case, I am afraid that this permission has no valid because of the law and do I have to convert the studio into the garage again to meet the requirement of the law?

We are first house buyer and have no experience. We also got the offer from the seller already. We highly appreciate to get advices from you soon. Thank you very much!