Repairing Leaking Copper Pipes

Types of Copper Pipe Leaks

Copper pipes develop leaks from pinhole corrosion (caused by aggressive water chemistry or electrical grounding issues), failed solder joints, or physical damage from freezing or impact. Pinhole leaks appear as small green-crusted spots that weep water steadily. Joint leaks show water seeping from the connection between two pipes or between a pipe and fitting. Identifying the type of leak determines the best repair approach.

Soldering a Permanent Repair

For joint leaks, the best repair is to re-solder the joint. Turn off the water and drain the pipe completely. Use emery cloth or a pipe cleaning brush to clean the pipe and fitting surfaces until they are bright and shiny. Apply flux to both surfaces, assemble the joint, and heat evenly with a propane torch. Touch lead-free solder to the joint — when the pipe is hot enough, solder will flow into the joint by capillary action. Allow the joint to cool naturally; do not quench with water as this can cause the joint to crack.

Patching Pinhole Leaks

For pinhole leaks in the middle of a pipe run, you can cut out the damaged section and splice in new copper using two couplings and a short piece of pipe. Alternatively, use a push-fit (SharkBite-style) coupling for a tool-free repair — simply cut out the damaged section, deburr the pipe ends, mark the insertion depth, and push the fittings on. Push-fit fittings are approved for use inside walls and are a reliable permanent repair.

When to Repipe

If you are finding multiple pinhole leaks in your copper plumbing, the problem is systemic rather than isolated. Aggressive water (low pH or high dissolved oxygen) can corrode copper pipes throughout the house. In this situation, patching individual leaks becomes impractical, and whole-house repiping with PEX or CPVC may be more cost-effective. Have your water tested if pinhole leaks are recurring — a water treatment system may be needed to protect new pipes.