How to Connect PVC to a Cast Iron Soil Stack

Septic Tank Lateral Line Installation
Written By
David Young
David Young
Published: Jul 12, 2011
Updated: Nov 20, 2021
1 minute read

Things You Will Need

  • Nut driver
  • Flexible coupling

When remodeling, PVC is a popular choice due to its light weight, low cost and easy installation. Joining PVC to cast iron is also easy with the use of flexible couplings.

  1. Turn the clamp nuts on flexible coupling counterclockwise until the coupling is loose enough to fit over the largest diameter pipe.

  2. Slide the coupling over the end of the smaller diameter pipe. Slide the coupling up the pipe until it is flush with the end of the pipe.

  3. Line up the ends of the two pipes. Slide the coupling until it sits halfway on each pipe with at least a 1-inch overlap on the pipes.

  4. Turn the nuts on the clamp clockwise until the coupling is firmly attached to both pipes.

  5. Run clean water through the pipes while checking for leaks. Continue tightening the clamp nuts until all leaks stop.

Photo Credits

Comstock/Comstock/Getty Images

Comstock/Comstock/Getty Images

David Young

David Young has written for the website for the Save Darfur Coalition and is currently writing articles for various other websites. Young holds a Bachelor of Arts in philosophy from Western Carolina University.

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