One of the biggest questions in off-campus housing is figuring out who you are going to live with. Some people find their roommates through clubs or their freshman dorms, but many don’t.
Some dorm-style apartments allow you to rent a room as one person and find other people for you to live with. However, this is often a pretty expensive option.
The next option is Facebook. There are many enormous groups of Berkeley students that do basically the same thing but have slightly different rules. Many require you to input your Berkeley email address in order to get in and it can take a few days to be confirmed, but these groups tend to have more students in them rather than companies. Lots of people need to find another person for a housing group or to replace someone that’s moving out
You can post either as someone seeking housing/a room/a group or as someone with a listing. Typically, the more in demand position posts, so seekers post for summer sublets, and people post listings for things during the school year
There's always turnover happening because of graduations, early graduations, taking a semester off, study abroad, et cetera.
Here are some of the groups:
Free and For Sale: the biggest group, mostly for selling stuff, but also has many housing posts, 55k members, need Berkeley email
https://www.facebook.com/groups/266259930135554/
Housing, 34.6 members, need Berkeley email
UC Berkeley off-campus housing, public group with 43k members
https://www.facebook.com/groups/ucberkeleyoffcampushousing/
UC Berkeley Housing, Rooms, Apartments, Sublets
https://www.facebook.com/groups/175275043279901/