13 yr old lab

Question
I have a 13 yr old lab who has always been good with controlling her bladder/bowels. In the last few weeks she has started going in the house from time to time and her schedule/environment has not changed any. Is this an age related issue behavioral or could it be physical?

Answer
The short answer is, yes, it can be age related, behavioral or physical.  Since your pet is not able to tell you how they feel (physically or mentally), it's best to use a veterinarian to get them to "speak".  

Physical exam, fecal exam, bloodwork and urinalysis is the first place I'd recommend to start.  With this information I can tell if she is concentrating her urine (then it would be more likely a behavioral issue) or not concentrating her urine (a physical issue).  I could tell if she was in significant pain (both a behavioral and physical issue).  I could tell with a thorough history if she is showing signs of dementia ( a behavioral issue) or I could tell if maybe she is sick with disease, weak from anemia or a heart condition (definitely physical issues).  

There are so many reasons that an older pet can loose their housetraining and a good many of them are physical ailments that can be helped. With my dear, departed, 17 year old Pepper it was dementia that caused him to loose housetraining in the end.  But it was pain and arthritis that started it when he was 15.

Good luck to you and I hope all works out for both of you.