Is it easily accessible? If so, you can repair it 2 ways. Get 2 PVC couplings and a piece of Sched 40 pipe, cut out the bad section and solvent cement the repair pieces in. Another way is to use a compression coupling. It is a PVC cylinder with gaskets and twist connectors on the end. Cut the pipe, separate the coupling and put the cap on the ends, the gasket and then slide the coupling over the cut. Tighten the ends. They are very good for low pressure use.