What you are trying to do is get an idea of the pulse of the foreclosure market in your area. I am not sure if you are talking about mortgage foreclosures or tax foreclosures...however the rules are the same: go to local auctions and join the local real estate club in your area and ask around.

At the auctions it will be easy to tell if there are alot of investors. Look for properties consistently selling for close to market value.

I don't have experience in the San Francisco area but its likely that there are alot of investors. Stick with smaller counties as that will help you avoid competition.

Warmest Regards,