How reasonable is it to limit a 650 sq ft apr to only 2 adults?

[Johann Jells]

I just declined an applicant who were a family of 4 adults, parents and 2 children for a 650 sq ft $1700 2 bedroom. It seems to me wear and tear, water and usage of the shared laundry and yard of the 3 family house would be problematic. Am I being unreasonable? My wife thinks I sometimes filter out lower class people too harshly.  If it were a family with minor children I would see it differently.