How to Repair a Cast Iron Pipe Leak

Major repairs require a professional.

Cast iron pipes last for a long time, but this does not mean they cannot become damaged and start to leak. Leaks are usually caused by corroding sections, often around the leaded joints. A do-it-yourselfer can repair small leaks in joints and small holes, but a professional should handle large leaks. Cast iron pipes need proper care and maintenance in order to last.

Things You'll Need

• Cold chisel
• Hammer
• Wire brush
• Clean rag
• Cast iron repair paste
• Putty knife
• Two-part plumber's epoxy

Instructions

Leaking Joints

1. Turn off the water supply to the pipe. Tap the joint lightly with a cold chisel and hammer. Cast iron pipe joints are soldered with lead; use a cold chisel to push the lead back into the joint.

2. Clean the repair area by removing rust with a wire brush and dusting away debris with a clean rag.

3. Fill the leaking area with a cast iron repair paste applied with a putty knife.

4. Let the area dry before letting water or waste reenter the pipe.

Holes

1. Remove all rust and corrosion from the hole with a wire brush. Dust away debris with a clean rag.

2. Apply plumber's epoxy around the hole so the patch is flush with the existing area, using a putty knife. Follow the manufacturer's instructions on how to mix the epoxy.

3. Let the area dry before letting water or waste reenter the pipe.

Tips & Warnings

• Do not disturb the pipe's supports. If the cast iron pipe supports are disturbed, the heavy pipe could fall down, injuring anyone in its way.

• Call a professional to repair sections of pipe or large repairs.

• Waste pipes contain toxic waste that can be hazardous to your health.

References

• "Complete Plumbing"; Stanley Books; 2003