Relining is the process of repairing damaged sewer pipes by creating a "pipe within a pipe" to restore function and flow. Epoxy relining materials mold to the inside of the existing pipe to create a smooth new inner wall, similar to the lining found in food cans.

Many times, pipe relining can be performed through a building's clean-out access and often requires little digging. Pipe relining may be used to repair root-damaged pipes, seal cracks and holes, fill in missing pipe and seal joint connections underground, in roof drain pipes, in storm lines and under concrete. The relined pipe is seamless and durable, and all materials used in the relining process are non-hazardous.