How to Repair a Leaking Water Supply Line

Turn off the water supply, drain the line, then either replace damaged fittings or cut out the damaged section and install new pipe with appropriate couplings.

  1. Kill the Water First. Locate the main water shutoff valve for your home and turn it clockwise to close it completely. If the leak is isolated to one fixture, you may be able to use a local shutoff valve instead. Turn on faucets throughout the house to drain remaining water from the lines.
  2. Find the Leak Source. Follow the water trail back to its source. Look for dripping, spraying, or wet spots along visible pipes. Check joints, fittings, and connections first as these are common failure points. Use a flashlight to inspect areas behind walls or in crawl spaces where pipes may be hidden.
  3. Choose Your Fix. If the leak is at a joint or fitting, you may only need to tighten connections or replace washers and gaskets. For pinhole leaks in copper pipes, a temporary patch kit can work short-term. Cracked or corroded pipes require cutting out the damaged section and installing new pipe.
  4. Get Supplies and Set Up. Based on your pipe type, get matching materials. For copper, you'll need pipe, fittings, flux, and solder. For PVC, get pipe, fittings, and PVC cement. For PEX, use crimp fittings or push-connect fittings. Clear the work area and lay down towels to catch any remaining water.
  5. Execute the Repair. For loose fittings, tighten with appropriate wrenches. For damaged pipe sections, cut out the bad section with a pipe cutter, leaving clean, square cuts. Install new fittings according to your pipe type - solder copper joints, cement PVC connections, or crimp PEX fittings. Ensure all connections are secure and properly aligned.
  6. Confirm It Works. Turn the water supply back on slowly and check for leaks at all connection points. Let water run through the system for several minutes, then inspect the repair area thoroughly. Look for any drips, moisture, or pressure loss. If everything looks good, clean up your work area and monitor the repair over the next few days.