From the Washington County (Oregon) Law Librarian:
Habitability questions we hear in the law library can be a broad as: what does a habitable apartment looks like? Or, as specific as: does an apartment have to have a window large enough for me to climb out?
There are a number of excellent sources of information on Oregon landlord-tenant law, online (e.g. this from the Oregon State Bar (OSB) and these) and in print (note: the OSB link has been fixed.) The latter print resources include Janay Haas’s “Landlord/Tenant Rights in Oregon,” which most public and law libraries have (unless their copies have been stolen – sigh) and some other landlord-tenant resources not online but available at your county law library.