PVC is a hard rigid plastic used to manufacture sewer lines and vent pipes used in the home. The pipes are joined together using PVC couplings, primer and cement (glue). Though very durable, if a heavy weight is placed on the pipe, such as someone stepping on the sewer line, it will crack or fracture, leading to leaks and health hazards. Fixing the broken area requires cutting out the damaged pipe and installing a new piece of pipe in its place.
Look for a damp patch below the pipe to locate the damaged area of pipe. There also may be an odor from the leaked wastewater. Mark the pipe 6 inches on each side of the fracture/break, using a black felt-tip pen. Cut though the pipe at both of the marks, using a hacksaw--or a power saw if there is room. Be sure the cuts are straight and scrape away any burrs from the cuts with a utility knife.
Measure the distance between the two cut pipe ends, and cut a new piece of PVC sewer pipe to the same length. Make sure the new pipe is the same diameter as the existing sewer pipe. Remove burrs with the utility knife.
Apply PVC primer around one outside end of the new piece of pipe and around the outside of one of the existing cut pipe ends. Then prime the inside of a straight PVC coupling. Wait 30 seconds for the primer to fully dry.
Wet the non-primed existing pipe end and slip a flexible rubber coupling fully onto the pipe end.
Apply PVC glue to all primed areas and push the coupling onto the glued/primed end of the new piece of pipe. Then push the other end of the coupling onto the end of the existing primed/glued pipe end. Hold in place for 30 seconds.
Slip the flexible rubber coupling onto the end of the new pipe (the new pipe end and existing pipe end will be in alignment). Make sure half the coupling is on the new pipe and half on the old pipe. Tighten the metal straps surrounding each end of the rubber coupling with a screwdriver.