How to Replace a Cast-Iron Sewer Pipe With PVC

Cast-iron sewer pipes are among the most common types of plumbing materials found in older homes. Most newer homes use PVC for the sewer pipes, as it's cheaper and durable, and it resists corrosion well. It's possible to replace a cast-iron sewer pipe with a PVC pipe by cutting out the old pipe and connecting the PVC using a flange. Replacement of a sewer pipe may require special permits. Check your local plumbing codes before proceeding.

Marker
Hacksaw or electric saw with fine-tooth blade
Respirator and safety glasses
Rubber flange
Screwdriver
PVC pipe

Instructions

- 1
  Turn the ball valve on the main water line 90 degrees clockwise to shut off the water while you work.
- 2
  Locate the section of sewer pipe that you want to replace with PVC.
- 3
  Mark the pipe where you want to cut it off and connect the PVC using a marker.
- 4
  Put on a protective respirator and safety glasses.
- 5
  Cut the pipe on the marks using a hacksaw or electric saw with a fine-tooth blade designed to cut cast iron.
- 6
  Pull out the old pipe and discard.
- 7
  Place a rubber flange over the end of the cast-iron pipe where you removed the old pipe. Tighten the worm-drive clamp around the pipe using a screwdriver. Turn the clamp until the connection is very tight.
- 8
  Place a section of PVC pipe into the other end of the rubber flange. Tighten the worm clamp around that pipe using a screwdriver. Turn the clamp until the connection is very tight. The transition between the existing sewer discharge line and the PVC is now complete. Install a second flange where the PVC pipe meets the street line or where the PVC transitions back to cast iron.

How to Replace a Ceramic Sewer Pipe

How to Remove Sand From PVC Supply Pipes

Plumbing