My dog is suddenly peeing in the house

Question
I have a dog who is potty trained and he has been peeing on the couch. Once he even laid in his urine. There has not been any reason for him to do this. No animals over and he is neutered. We take him outside to pee regularly. Could this be a medical problem?

Answer
Not knowing his age etc it is hard to say but most likely it is a problem with his bladder, hormones, lack of tone in the bladder, stones, etc.
He needs a work up and an xray of his bladder.

What he has is incontinence. He isn't peeing because he wants to he has uncontrolled leakage.