What do you guys think could cause my 5 year old bitch start to pee in her sleep?
I had her tested for all the usual suspects and nothing turned up.
She seems to feel fine and all her vitals are normal.
I had her spayed about 3 years ago and this just started?????

Could be spay incontinence.

One could also have her evaluated and adjusted by a veterinary chiropractor in case she twisted something: the bladder meridian runs down the spine. If that works, she won't need the Proin. There may be herbs that help; I have just used Proin on the older girls after the chiropractor isn't enough. The chiropractor worked for years, though, for my spayed girls, until they were in their teens. Mileage and results may vary!