Based on my subjective observations, homelessness definitely seems to have gotten worse in the South Bay Area in the past few years. If you go biking or walking along the various creek trails and railroad tracks you'll see more encampments. Some of them are fairly well hidden but if you stop and look you'll see the signs.

By the way, this is one of the reasons why it's tough to get people out of their cars and commuting by bike. Many people don't feel safe cycling through those areas.

I've been here for 8, my (totally anecdotal) observation is that a lot of the homelessness + drug use has moved up market from the mid market/tenderloin area towards duboce triangle and the castro making it more noticeable/visible. I wouldn't be surprised if the absolute numbers increased too but it seems like a lot of the development/companies that moved into the mid market area may have led to an increase in police enforcement that has led to a dispersion.