House urination

Question
We have 2 Brittany Spaniels - Female is Sheba, she is 10 years old and the Male is Sammy and he is 6 years old.  We have owned both dogs since they were puppies.  Both dogs began urinating in the house about 2 years ago, usually on the area rugs and/or hardwood floors and furniture.  They have ruined and we have removed all the area rugs.  This happens almost every day, but it never happens in front of us. We both work full time, but often from home, so there is not a long time where they are alone during the day.  We cannot always tell which one of them has made the mess.  They have been seen by the vet and are both in good health and there has not been any changes to their living environment.  We have a fenced in yard and they get plenty of outdoor exercise and go to the bathroom in a wooded area in our backyard.  They are both loving and behaved dogs in all other respects and are very playful with each other. We have tried a variety of discipline; extra outdoor activity; "no-go" sprays on the carpet, floors & furniture.  We love our dogs very much but we are at our wits end, can you please help?

Answer
You don't mention if your dogs are spayed and neutered, but even if they are males and females can easily determine one another's sex.  This may have begun with one "marking" and the other "marking over", or it may have been a legitimate "accident" by one which has precipitated this breakdown in behavior.  In order to determine which dog is the culprit (it may just be one, but at this point I doubt it) you can use vegetable dye.  Offer a small portion of food with green vegetable dye to one dog (the female, if the male is not neutered.)  If the male is the culprit, there will be no dye present.  If dye is present, you won't necessarily know that both dogs aren't the problem.  If no dye is present, you will at least have reduced your re-training to one dog.

Because your dogs (or one) have been demonstrating this problem behavior for such a long time (2 years), re-training requires indoor restraint, which means long, lightweight leads and your careful and constant observation.  Reinforce their appropriate elimination with praise/reward.  If the culprit (or both) is unable to resort to this unwanted elimination, and if both dogs are heavily praised/rewarded for every single appropriate elimination, over the course of several weeks you should see this problem extinguish.  However, you also need to bring this problem to the attention of the veterinarian, as inappropriate elimination in either sex may indicate a developing physical problem.