What You Should Know About Pinhole Leak in Copper Pipe

Pinhole leaks mainly form in copper pipes, and if you’re unlucky enough to find some in your piping, the best thing to do is cut away the leaking portion and solder on a new section.

This can be tough for those without DIY experience, and it shouldn’t even be attempted by a novice if more than 2 inches of piping exhibits leaks. That said, this guide can help you understand and handle pinhole leaks.

Identifying Pinhole Leaks

A pinhole leak will either result from a pipe corroding from the inside-out, from the outside-in, or from a defect that was made during manufacturing. If your copper pipes are over two decades old, or if you know your water has a pH or mineral imbalance, then you are more prone to be a victim of leaks. Pinhole leaks are notoriously hard to identify, but here are some clues for their existence:

• Surprisingly high water bills
• Sounds of dripping
• Unexplained condensation
• Pipe discoloration
• Mold or mildew growth

A more scientific approach to discovering a pinhole leak is to turn off your water supply and then check your water meter to see whether any water is still dripping out.

Replacing the Section of Leaky Pipe

You will need the following equipment to accomplish this procedure:

• Marker
• Tube cutter
• Cotton rags
• Measuring tape
• ‘Sweat’ coupling replacement pipe
• ¾” diameter wire fitting brush
• Solder wire
• Propane torch

All of the above should be available and affordable at your hardware store, but the trick is in actually replacing the pipe, which takes more skill and time than many realize. You need to cut out the leaky pipe and solder on the new, a process known as ‘sweating’. More specifically, you need to:

1. Mark the leak on the pipe, plus the area which you want to cut
2. Shut off the water main
3. Drain the water in the pipe (try turning on the faucet at the lowest elevation in your house)
4. Using the tube cutter, cut and remove the marked-off section of pipe
5. Dry and stuff the pipe with the cotton rags, and do not remove them until ready to fit on the replacement pipe
6. Measure the length of the new gap in the pipe
7. Measure and cut out a portion of the sweat coupling replacement pipe that is 1” longer than the the gap measure
8. Smooth the rough edges of the replacement pipe with the cutter
9. Smooth the rough inner edges of the replacement pipe with the wire fitting brush
10. Clean and smooth the cut sections of copper pipe
11. Slide the replacement pipe onto the copper while making sure about ½” of the replacement pipe fits over the old section
12. Solder the new joint by holding the torch to one side and the tip of the solder wire to the other until enough of the wire melts into the opening to completely fill it
13. Turn on the water and test the repair

Preventing Pinhole Leaks in Future

It’s easier to try and prevent pinhole leaks than it is to fix them, but there is no sure-proof solution. To decrease the likelihood of such leaks forming you could install a water softener to treat the water that runs through the pipes. More neutral water is less likely to erode the copper. 

Making sure your pipes are installed correctly in the first place is also critical. For that, you need a reliable plumber. If you live in the Cleveland area, then call Ohio Buckeye Plumbing at (440) 283-9377 to get in touch with a team who has over 20 years of family-run experience.

• Published at February 23, 2022
• Category: Plumbing Faucets