Hi. A very similar question was asked a couple of days ago. Your landlord is responsible for repairing leaks and should also have a procedure in place to mitigate water damage (example throughly drying out the apartment) to prevent microbial growth.
I would suggest you contact the San Francisco Rent Control Board to discuss with them your options http://www.sfgov.org/site/rentboard_index.asp
Alain Pinel Realtors