There are a number of frogs and toads that live primarily on dry land, and can get along well with just an occasional rain water supplied drink. Some of them tend to be nocturnal, spending the day light hours out of the direct sun to avoid getting dehydrated.
Here in Michigan we have several different species of toad as well as some tree frogs -
I've had a family of tree frogs living in my shed for about the past ten years.
---------- Post added at 06:25 AM ---------- Previous post was at 06:17 AM ----------
Just out of curiosity, I took a look and it seems like you have tree frogs in your neck of the wood as well -
ODFW Conservation Strategy Frogs and Toads
Pacific Treefrog (Pseudacris regilla)
The Pacific treefrog is the most common frog in Oregon; it is the only frog found in all eight ecoregions. In dry areas, it is found in places high in moisture—marshes, meadows, woodlands and brush. Pacific treefrogs are a fabulous example of what the Oregon Conservation Strategy hopes to accomplish for all our common native species—that is, keep them common.
Fun fact: Pacific treefrogs are often heard on movie soundtracks. You may hear them sing in the spring!
Lives: Throughout Oregon