How to Replace Clay Drain Pipes With PVC

Clay drain pipes can be replaced by PVC sewer pipes that are either the same diameter as the old clay pipes, or a smaller diameter that is approved by local city laws.

PVC pipe can replace old clay sewer pipe, using a flexible coupling.PVC pipe can replace old clay sewer pipe, using a flexible coupling.
The old clay pipe will have to be cut, a flexible coupling installed to the end of the clay pipe, and then a new PVC sewer pipe attached to the other end of the connecting coupling. New pipe and couplings can then be primed and glued to this PVC pipe, so that it reaches the necessary water fixtures in the home.

Cut completely through the old clay pipe at the required location--use a reciprocating saw, with a carbide blade. Make sure that the cut is straight. Now cut through and remove all areas of clay pipe that you want to remove that are leading to water fixtures.

Push a flexible coupling onto the end of the existing cut clay pipe. Tighten the metal strap around the end of the coupling by turning its screw clockwise.

Push a new piece of PVC sewer pipe onto the other end of the flexible coupling, and again tighten the metal strap by turning its screw clockwise.

Connect all necessary PVC couplings and new PVC pipe to this new pipe, so that all water fixtures in the home (shower, toilet, sinks, etc.) run into this new PVC sewer line. At each coupling, first prime the inside of the coupling and end of the pipes with PVC primer, and wait for it to dry--usually 30 seconds. Then apply PVC glue to all primed areas before pushing the pipes into the ends of the coupling, and holding for 30 seconds.

Things You Will Need

  • Reciprocating saw & carbide blade
  • Flexible rubber coupling
  • Screwdriver
  • PVC sewer pipe & couplings
  • PVC primer
  • PVC glue

Tips

  • Every horizontal piece of sewer line has to be installed at a gradient so that waste can travel down the sewer pipe. Check with the local city laws for the correct gradient (usually one inch per 10 feet of sewer line).
  • If the new PVC sewer line is a smaller diameter than the old clay drain pipe, use a flexible reducing coupling to connect the two together. This coupling will be the same diameter as the clay pipe on one end, and the diameter of the new PVC pipe on the other.

About the Author

Steve Sloane started working as a freelance writer in 2007. He has written articles for various websites, using more than a decade of DIY experience to cover mostly construction-related topics. He also writes movie reviews for Inland SoCal. Sloane holds a Bachelor of Arts in creative writing and film theory from the University of California, Riverside.