I know this campus well. The culture is such that single-sex houses are more of an anomaly that co-ed houses. DKE, at least, has had female residents since 2004. Some groups may choose to be unhoused rather than operate a coed house.
There is one local sorority as well as NPHC groups:
http://rhoepsilonpi.com The NPHC groups do not have housing, and as far as I know, they have never sought it.