Sudden housebreaking issues - behavior problem or something else?

 I don't have any suggestions Tracy; just wanted to wish you luck in finding as answer. Hopefully she can have more time out of the crate again soon.

Tracy, I don't have any suggestions either but I think crating her is a good idea (as long as she doesn't break out). You mentioned urine testing, did you have any blood work done?

You ruled out a UTI.  I would probably have blood work done as Tina mentioned.  Have her thyroid checked too.  Has her water intake increased?  

Have you noticed any changes in other areas of her behavior?  Has anything changed in the neighborhood?  Construction near you? New noises that might be making her get anxious or excited.

I'd continue to crate her when you're gone.  I'd do that for two months and then try again with leaving her loose.  I'd start with fairly short lengths of time.  A couple of hours at first.  

I'd also start praising and giving her a treat every time she goes potty outside.  Most of us stop rewarding and praising on a regular basis once our dogs are housetrained.

If none of the above helps, I'd see about doing some more extensive testing on her urinary system to rule out bladder stones, etc.   Your vet would be the one to advise what else might cause her to be having accidents inside if it's not behavioral.

I hope she's just regressed a bit and with some remedial housetraining she'll get back to being trustworthy.  

She had blood work done when she had her dental last month.  It was fine.  However, something they've pointed out whenever she has blood work (even the first test she had when we adopted her in 2011), is that she has two markers that are on the borderline abnormal side.  I forget now which ones they are, but apparently, they can indicate dehydration.  Again, it's borderline, so the vet wasn't worried.  She just advised us to add some water and canned food to her kibble to add some moisture.  

Perhaps this is related to those blood markers, but the other thing they've noticed in her urine tests (this week and before) is that her urine is pretty concentrated.  Again, we were advised to make sure she's hydrated enough.  She always has fresh water available, except when she's in a crate.  She seems to drink mostly in the afternoons and evenings, but at a steady rate as far as we can tell.

We tried to think of changes that might be stressing her.  No neighborhood changes or construction that we can think of.  Our routine is the same, and her other behaviors are the same.  The first time she broke out of her old crate was a day we had outdoor plumbing work going on, so we assumed that triggered it (then she kept doing it once she figured out how -- thus our decision to leave her out).

We always verbally praise her when she goes potty outside, and she usually runs right in to get a treat from the treat bowl by the door.  But, maybe she thinks she's being rewarded for coming in the house, not the actual peeing.  I'll try carrying treats out with me when we go on potty breaks.

Thanks for the suggestions.  We'll use the crate for a while now and see how things go.  We've got houseguests next week, so we won't want to alter her routine too much then.  It's baffling -- and annoying, since our carpeting is less than 2 years old!

Tracy, I don't have any recommendations either, but wanted to send my  support.

Tracy I don't have any info to help. So did it start after you started adding more water to her food, etc?

Is the urine at the accident site still very concentrated or is it less concentrated than her normal  times?

The fact that is is always at the same time of the day must be relevant. I hope you can figure it out and it doesn't indicate there is anything to worry about

Wow, this is a tough one, you are doing everything right, rule out any physical issues then maybe just start over crate her for awhile and hopefully things will go back to normal. I had a similar case with a client's dog and they ruled out everything then just started crating again and in about 2 months of using the crate again, they started letting her out and she stopped the behavior. Good luck and please keep us posted.