How to Repair a Pinhole Leak in Copper Pipe

Pinhole leaks are the classic basement surprise. They usually appear as a tiny, pressurized spray or a slow, rhythmic drip caused by internal corrosion or sediment buildup. Because copper pipe is thin, you cannot ignore these; they only get larger, and left alone, they lead to catastrophic water damage and expensive structural repairs. Fixing this is a rite of passage for homeowners. When done well, the repair is as strong as the original line and will last for the remainder of the pipe's service life. You do not need to replace the entire run of pipe; you simply need to bridge the gap and seal the integrity of the line using the right fittings and a clean connection.

1. Kill the Water Pressure. Locate your main water shut-off valve and turn it clockwise until fully closed. Open the highest and lowest faucets in the house to bleed the pressure out of the lines.
2. Remove the Compromised Copper. Use a tubing cutter to excise the section of pipe containing the pinhole. Ensure your cuts are made on clean, straight pipe at least two inches beyond the leak on both sides.
3. Polish for Perfect Adhesion. Use a round file or the reaming blade on your tubing cutter to remove all burrs from the inside edges of the cut pipe. Sand the outer ends with emery cloth until the copper is bright and shiny.
4. Position the Coupling Bridge. Slide a slip-coupling over one end of the pipe, then align the second piece and slide the coupling back over the gap. Ensure the coupling is centered equally over both cut ends.
5. Solder the Permanent Seal. Brush a thin layer of plumbing flux onto the pipe ends and the inside of the coupling. Apply heat with your torch to the coupling until it glows slightly, then touch the solder to the joint seam.
6. Verify the Leak Is Gone. Once the solder has cooled for a few minutes, wipe away excess flux with a damp rag. Slowly open your main water valve and check for any signs of seepage.