Depends on the school. Some (like USC or BU) are notorious for having poor patient pools and students nearly having to pay out of their pocket to get a patient in their chair so they can do a procedure. Others (like NYU) are favoured for the fact that they have very large, active, willing patient pools, and their upper-year students will harbour patient lists of 30-40 people and remain quite busy. I'm not sure if you should ask administration or faculty the question (since schools who have few patients probably don't like admitting it) but asking a student might be a good idea.
USC does not have a poor patient pool. I don't know where this misconception comes from. USC is 1 mile away from downtown LA, in the 2nd largest metro area in the US. The problems at USC in the clinic are related to administration, excessive requirements, lack of faculty, etc. I challenge you to find a school with a better patient pool. There are plenty of things to criticize USC for but this is not one of them. Just looking to clear this up.