ThetaXi -
Here is a link to the Tenants Union, which is based in Seattle. You can call them at (206) 723-0500, or go by their office at 3902 S. Ferdinand St. in Seattle. They are a nonprofit so be patient if you can't get through.
http://www.tenantsunion.org/
I found the definitions of the Washington LandLord Tenant Act and though it doesn't specify fraternity houses, it does mention housing in conjunciton with education
http://search.leg.wa.gov/wslrcw/RCW%...018%20.040.htm under number 1.
However, as everyone said, GO TO A LAWYER.