You always get SOMETHING that likes to nibble irrigation or water pipes. My father is a camp ranger and everytime he turns on the water at camp in the spring, he ends up having to track down the holes in the lines due to the porcupines. water pipe? OM NOM NOM!

They also like to eat the latrine doors.

Despite seeing the damage, I've never actually SEEN a wild porcupine however since they're nocturnal and aboreal.