Thanks for the response Raiko. The dogsitter is actually a friend, who gave him too much freedom. She let him run around her house, and before she knew it, he was peeing all over her house, too - but she didn't try to correct him.
We put him in a confined space, and he usually goes on his Wizdog (his toilet training system), but now, he's going everywhere EXCEPT his Wizdog within the confined space, and now we can't trust him running around any room anymore. It seems like he is peeing around the room for fun, now....