I would suggest a two-pronged approach, Leah. You can spray the pipes with something like Bitter Apple spray, which won't hurt the pipes but will make them taste bad to him. But you should also have active play with him when he is outdoors. Teaching your puppy to retrieve a ball, toy, or Frisbee will help cure his chronic chewing problem. Good luck!

You're welcome, Leah. Check the bottle for how often to spray. I believe they also may make a salve that may last longer.