4 adults, 3 kids in one bedroom unit?

I am a neighbor and am concerned. A father his girlfriend (not the kids bio mom) and son live in a one bedroom 600 sq ft unit with a husband and wife and their two kids. That's 7 people. Apparently the kids sleep on the floor and the adults take turns sharing the bed and couch bed. They have the same 600 sq ft unit I have. I can`t imagine 7 people in this tiny duplex. Is this violating laws? I was considering calling CPS. I do not know whom their landlord is as these are separately owned how could I also find that information?