How to Repair a Drain Pipe

Updated February 21, 2017

Behind walls, below sinks and beneath showers, leaking drain pipes cause damage to a home's structure and create an attractive environment for mould and mildew. Because fixing drain pipes requires a only few basic tools and novice-level plumbing skills, do-it-yourselfers stand to save big bucks by gaining basic drain pipe repair skills. Whether you're fixing cast iron or plastic, learn how to repair a drain pipe and you'll be prepared to tackle increasingly difficult plumbing projects.

Clean the exterior of the drain pipes and the interior of the pipe fittings. Rub a piece of emery cloth around the outside of each drain pipe's end, as well as around the interior of the pipe fittings. Wipe the end of the pipe and the pipe fittings with a clean cloth to remove dirt, shavings and other particles.

Apply a thorough coating of pipe welding glue around the exterior of a pipe's end as well as to the inside of a pipe fitting, using the glue applicator brush and circling at least twice to ensure even distribution.

Press the fitting onto the pipe or the pipe onto the fitting. Push the pieces together until the interior lip of the fitting butts against the edge of the pipe. Rotate either the pipe or fitting 1/8-turn to spread the glue. Hold the pipe and fitting firmly in place for 30 seconds. Release the pipe and fitting and allow the joint to cure 10 minutes before handling. Repeat to create additional joints.

Clean and deburr the ends of cast iron drain lines using emery cloth. Rub emery cloth around the outside of the pipe's end, removing burrs and smoothing inconsistencies. Wipe the end of pipes with a clean cloth to remove metal shavings, dirt, grease and other particles. Wipe the interior of flexible drain connectors with a clean cloth.

Press a flexible drain connector onto the end of a cast iron drain pipe. Push the connector until its interior lip abuts against the end of the drain pipe. Insert a flathead screwdriver into the connector's clamp screw. Tighten the screw until hand tight.

Insert a second pipe into the open end of the flexible connecter. Insert a flathead screw into the loosened connector clamp screw and tighten until hand tight.


Read your pipe's markings to determine its plastic type. ABS and PVC require different types of glue.

Things You'll Need

  • Emery cloth
  • Clean cloth
  • Pipe welding glue
  • Flexible connectors
  • Flathead screwdriver
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About the Author

Based in Hawaii, Shane Grey began writing professionally in 2004. He draws on his construction experience to write instructional home and garden articles. In addition to freelance work, Grey has held a position as an in-house copywriter for an online retailer. He holds a Bachelor of Arts in theater arts from Humboldt State University.