Eli - our 6 mo boxer - pees a lot if we're home to let him out as much as he wants... He wants to go out a lot and always pees when he's out. But if we leave for work, he's fine in his crate until we get back.. hours later. He also drinks A LOT more water than our other two. He's been to the vet and he's fine. I just think he might be normal like our Eli. Just drinks a lot and pees a lot.

Eli did seem to pee more the first week or so we had him.. and now its not as much.. but definitely more than our other two. I also figured its because he's still young.. and intact. But he's definitely peeing.. not marking. I'd say your foster dog is normal.. just like E.. he just has to go.. =)