Does it matter where I get my BSW if I plan to go to grad school?

It depends on how stiff the competition is at the school where you want to get your MSW. If they have similar applicants, they may tie break by deciding which one had the most competition for grades. Out of California, however, most people do not understand the difference between a state university and a UC. If you apply in California, most will consider the UC better as the entrance requirements are higher. You would be better off at a UC.