From the Washington County (Oregon) Law Librarian:
Rental property Habitability questions can be separate from Repair questions for landlord and tenants, but the two can overlap, as you might imagine.
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.