My husband and I rescued Griffin from BRAT when he was 9 months old. He is now 1 year and 2 months old. When we first got him, we dealt with some minor behavioral issues and resolved them all - including housebreaking. About a month ago, Griffin developed a UTI. We realized there may be a problem when he was having accidents all the time (he rarely did before) and was going to the bathroom frequently on his walks. We took him to the vet and he was put on medication for 10 days. Right around the time that he was coming off the medication, my husband had some minor surgery and was home from work for 3 weeks. While my husband was home - Griffin had NO accidents and was a perfect dog. Now that my husband is going back to work on Monday, we started going out for 1 - 2 hours at a time so that Griffin can get used to being alone again. Each time that we've left him at home, he's had accidents (both #1 and sometimes #2) and now we think it's a behavioral issue (maybe separation anxiety?) that we're dealing with. Before we leave him alone, we walk him and leave him some treats or a bone with peanut butter in it (to distract him as we leave the house). We keep him gated in the hallway outside of our bedroom since he does not like being in the crate (he used to poop in it when we left him in there). Does anyone have any suggestions on how to deal with all of this pee? We are getting really tired of it and want him to be housebroken again. He's done it before and I know he can do it again. I've even gone back to treating him when he does something outside to reinforce the good behavior. The longest he ever goes alone is 4 hours since i come home in the middle of the day to walk him. But, he can't even stand to be alone for an hour by himself.
Make sure that he doesn't have another UTI…. the stress if it is separation anxiety could be the problem and most likely it is... but first make sure it is not anything physical first. Sometimes UTI's come back and sometimes they are very, very hard to clear up totally. Also you should strip test him for Fanconi just to be sure, while typically it is later onset, it can happen at a yr old
After he was on medication, we took a urine sample to the vet and he was cleared with any infection. I called the vet again today to get her opinion on this situation and she agrees it definitely behavioral. Over the last few days, he's been pooping when we leave him alone too (despite doing everything during his walk before we leave). Does anyone have have suggestions on how to calm down a dog who gets anxious when left alone? He's also recently started to get destructive too - today he pushed down the gate into our bedroom and ate half of our wicker waste basket!
sounds like separation anxiety. You might try using a crate so he has less space; it might make him more comfortable to have less space, believe it or not!
There is a thread here somewhere about how to go about desensitizing a dog to being alone. It takes a lot of work, and very small steps. If you can't find it, let me know, and I will make another post.
Experts tell us that it can take up to a year for rescue dogs to settle into their new homes, sometimes. When they find something they really value (their new family) they are afraid when the people leave that they won't come back. Hang in there. Have patience 
Oh, and try the DAP plug ins. They produce a calming pheremone to relax a nervous dog. You can look online, or find them at some pet supply stores. I have no personal experience with them…I keep meaning to try it...but lots of people have very good reports about them.