Nighttime Urinating

A UTI (Urinary Tract Infection) can develop in less than 2 months, so i'll say is back to the vet. Specially when he is already 8 years old

 I will probably take him back, but it doesn't make sense that the UTI would only affect him at night.

He could have something else going on that is causing him to lose bladder control when he's sleeping.  I suggest a Vet visit.  Might not be a UTI but there are other things that could cause incontinence, especially in older dogs. 

 I'm planning on another visit, but that doesn't make sense that it's in his sleep. I caught him this morning doing it and he pawed at the towels first and then peed while standing on them. So I'm pretty sure he was awake.

 Behavioral changes do not happen out of the blue. If you think it's behavioral, what has changed in your dog's life? Have there been any changes in his environment?

 Nothing has changed in his life. The last big change was a year and a half ago when we moved. But we've only had him for 2 years and I'm pretty sure he has been doing this for awhile, because when we moved our under bed storage had urine in it which meant he was doing this before. But I didn't catch him then and he was crate trained during the day then so it could've been during the day while we were gone. He's a great dog otherwise and I will continue to clean up after him, but if there's a way to stop it I'd like to try that.

So maybe he has never been 100% house trained. What do you do when you find he has peed in the house? I would suggest you consider him an unhouse trained dog and start from scratch like you would with a puppy and be sure to completely eliminate all the urine odour from the house. You may have to start getting up during the night to take him out and confining him when you are away. He maybe hiding his pee spots from you so give your house a good check over. Do you know the history of this dog? Did his previous owners have the same problem?

 Typical I find his blankets are wet and I don't do anything but wash the blankets because what could I do. The one time I caught him I put him outside immediately. He only pees at night in the bedroom, he has never peed in the living room. He is crated during the day when we are gone. He has only messed in there a couple time in the last year. He has a problem with separation anxiety which is why he is crate trained. The place isn't very big so he couldn't really hide it. When we got him we were told he was part of a program with local zoo until the program got cut, and that he stayed the night in a office. I don't know how he spent his days inside or out, but we have never had a problem with him going inside while we are awake. He lets a know he has to go out, and he whimpers to wake us up when he has to poop. I don't know how to house train him when I almost never catch him in the act since I'm asleep

Deweyj

I don't know how to house train him when I almost never catch him in the act since I'm asleep

You don't have to catch a dog in the act to house train. The #1 rule is to never allow accidents to happen. You have to make sure he is let out often enough to avoid any chance of an accident - 2 hrs, 4hrs?  Every time he goes to the bathroom outside you praise him like crazy and give him a reward (treat). If he does pee inside don't yell or punish him in anyway. This will only encourage him to find a quite, out of the way spot to avoid the punishment. Urine odour is hard to remove. There are products you can buy. If his blankets are wet then there is probably urine odour on the floor as well. so use the product there.

I would only add that IMO if he is peeing on his blankets it may very well be that he is eliminating in his sleep. Dogs don't typically pee where they sleep. My sisters dog had Cushings disease and that is what he did. Your dog may just not have very good bladder control. It happens to the best of us as we age.

Although you had your dog to the vet recently, if you did not mention the urinating problem he wouldn't necessarily find something in a regular check.  

 Border Collies are smart dogs and don't always learn what you think they are learning.  This dog may have learned that when his people are with him, he should ask to go out.  But, when his people aren't there, or are asleep, he may not know what to do.  You will never retrain him without supervising him any time that he is loose in the house, so you may have to go back to using the crate at night.  If it's in your room, you can set your alarm, take him out with no fuss, and just put him back after he's gone outside.  When I'm training a dog, I leave a pair of sweats and some muck boots next to the bed;-)  The best product I have found for eliminating odor is Petastic.  If he was pee'ing in his sleep, I'd say he might have insufficient sphincter control, but if he's doing it while awake, he may just not be able to hold it well, or doesn't realize that the bathroom is outdoors at night, too.  Do have him checked for kidney function, though.  Sometimes an older dog will be incontinent at certain times because of differences in intake of fluids during the day.  That can even happen with normal dogs - my hound can lay on the couch all day, but between six and eight in the evening, he wants out several times.

I would set an alarm and take him out during the night.  If medical problems are ruled out, maybe start setting the alarm a little later each night until he is sleeping through the night.