User blog comment:Thailog/Ep. 206 "Bloodlines" discussion/@comment-137.154.16.31-20120605062055/@comment-67.6.97.179-20120607032000

Maybe, or he could be living in Clark Kent's apartment. In the BtAS and JLU Supergirl stayed in his apartment for some episodes, but only one episode which escapes me at the moment.

He does look over 18 so he could also be living in his own place.