GROUND SQUIRRELS! I had heard about this, but had never experienced it. A customer called us up thinking he had a broken pipe due to a freeze in the line. However, what we discovered was that a furry little enemy had chewed up the sprinkler pipe and caused a big flood in his yard. We fixed it, and called it good. A week later he called again with the same synopsis. Turns out the furry enemy was at it again! We found the leak, fixed the pipe, and it lasted all summer. In the picture you can see the 2 separate attacks on the tasty poly pipe!