A leaking copper 90 fitting can be a frustrating plumbing issue that can lead to water damage and increased utility bills if left unaddressed.

However, with the right tools and techniques, fixing a leaking copper 90 fitting can be a manageable DIY task. In this blog, we will guide you through the steps of fixing a leaking copper 90, offering new ideas and advice to ensure a successful repair and prevent future leaks.

Identify the Source of the Leak

Before diving into the repair process, it is crucial to accurately identify the source of the leak. Leaks in copper 90 fittings often occur at the soldered joints, where the fitting connects to the copper pipe. Thoroughly inspect the area around the fitting and look for signs of moisture or water stains. This will help you pinpoint the exact location of the leak and determine the appropriate repair method.

Prepare the Work Area

To ensure a smooth repair process, it is essential to prepare the work area properly. Turn off the water supply to the affected area to prevent further leakage. Clear the surrounding area and ensure there is ample space to maneuver and work comfortably. It may be necessary to drain any remaining water from the pipes to minimize water damage during the repair.

Cut and Remove the Leaking Section

To fix the leak, you will need to cut and remove the leaking section of the copper pipe and the 90-degree fitting. Use a pipe cutter to make clean and precise cuts on both sides of the leak. Make sure to measure and mark the pipe accurately before cutting to ensure the proper length for the replacement fitting.

Clean and Flux the Pipe Ends

Once the leaking section has been removed, clean the pipe ends thoroughly using emery cloth or a wire brush. This step is essential to remove any debris, oxidation, or old solder that could affect the integrity of the new joint. Apply flux to the cleaned pipe ends to promote proper solder adhesion during the soldering process.

Solder the New Fitting

With the pipe ends prepared, it’s time to solder the new 90-degree fitting into place. Apply a small amount of soldering paste or flux to the fitting and slide it onto one of the pipe ends. Use a propane torch to heat the joint evenly, allowing the solder to flow and create a watertight seal. Ensure that the solder fully penetrates the joint and creates a secure bond. Repeat the process for the other pipe end.

Inspect and Test the Repair

After soldering the new fitting, inspect the joint to ensure a proper seal. Look for any signs of incomplete soldering or gaps that may cause future leaks. Once satisfied with the repair, turn on the water supply and closely monitor the joint for any signs of leakage. It is advisable to observe the repaired area for some time to ensure the repair holds up under normal water pressure.

Prevent Future Leaks

To prevent future leaks, consider applying a pipe thread compound or Teflon tape to the male threads of the fitting before connecting it to the pipe.

This added layer of protection helps ensure a tight seal and minimizes the risk of leaks over time. Additionally, regular maintenance and inspections of your plumbing system can help detect and address potential issues before they escalate.


Fixing a leaking copper 90 fitting is a task that can be accomplished with the right knowledge and tools. By accurately identifying the source of the leak, preparing the work area, cutting and removing the leaking section, soldering the new fitting, and conducting thorough inspections, you can successfully repair the leak and restore the integrity of your plumbing system.