7 year old Dachshund lifting leg in house

Question
Hi,
I have a 7 year old neutered  mini dachshund that has just started lifting his leg.  He has always squatted to pee in the past.  He now lifts his leg in the house and pees on my comforter, corner of the computer table, the door to his crate when its open, and other places. He has NEVER done this before.  We would leave pee pads down when it rains or snows but he was good the rest of the time.  We just took him to the vet and they checked him over and did a urine test all was fine.  Nothing new has happened that we can figure out.  We do have another neutered 2 year old dachsund and they get along fine.  If you can give us any suggestion we would appreciate it.  Thanks  

Answer
This sounds like urine marking behavior and is probably due to the other dog having reached social maturity at age 2, so your older dog is letting him know that he thinks the territory belongs to him.  I would put the older dog on a lead tethered to your waist, and go back to house training 101 (not that this is a house training issue, just that you want to govern where he roams and not let him get the opportunity to mark).  Clean any urine up with Petastic or some other enzymatic cleaner so that he won't be attracted back to the smell.