Pinhole leaks in copper pipes often don’t show to the naked eye. Sometimes, they’re not even detectable with a magnifying glass. They do, however, offer clues to their existence. One thing that happens is that your water bill increases suddenly and unexpectedly. If you make the rounds to check your sinks, then also be sure to check that you have neither a running toilet nor a “ghost” toilet. These and other sources of hidden running water can contribute the issue. If you have none of these other things happening, then a pinhole leak is the likely culprit.

Also, check for weird condensation around your water heater, especially in the winter when the chilly temperatures highlight such condensation. Listen for sounds of dripping from your water line. If your pipes have frozen, then it’s possible that even a brand new copper pipe will develop a pinhole leak. There might also be mold and/or mildew around certain sections of pipe or on the walls or floor near an affected section of pipe. Plumbing can be persnickety even in new homes, so it pays to be attentive.

Fixing a pinhole leak in a pipe usually isn’t possible for the long term. Clamps, glues activated by heat, or any sort of patch might work for a very short period of time, but beyond that, the pipe will go back to leaking. The only option is to replace the leaky section of pipe, which is tricky.

If you’re a novice at DIY, then it’s a good idea to call a professional to do the work. Otherwise, you might spend a lot of time replacing the bad pipe only to wind up with another leaking pipe. Even if you’re an “old hand” at DIY, you should really call a professional to do the work if the section of pipe that’s leaking is longer than 2 inches (5.08 cm).

That being said, to do such a replacement, you’ll need several items from the local hardware store:

  • Propane torch
  • Solder
  • Wire fitting brush, 3/4-inch
  • Measuring tape
  • Replacement pipe with sweat couplings
  • Pipe cutter
  • Rags

Never forget to shut off the water and to drain the pipe before beginning this procedure! Once the water’s off, find the leak again. Mark off where to cut. Using the pipe cutter, slice through the pipe on either side of the pinhole leak. Stuff the rags into both ends of the remaining pipe. Then, measure and cut a piece of replacement pipe with the couplings, which should be 1 inch bigger than the gap.

Measure both the piece of leaky pipe that you removed and the space remaining between the two good sections of pipe. Make sure they match. Using the pipe cutter, smooth the outer edges of the ends of the piece of replacement pipe. Using the wire brush, smooth the inside of each piece of the remaining good pipe.

Next, attach the pipe with the couplings, ensuring that 1/2-inch of the couplings fits over each of the good pieces of pipe. Use the blowtorch and solder to seal off each end of the replacement pipe. Once the pipe cools, turn the water back on and make sure that it doesn’t leak.


Hard water is rough on copper pipes. While there is no “wonder treatment” or other solution that will permanently stop pinhole leaks, installing a water softener will extend the life of your copper pipes. Having a dehumidifier in the room with the pipes is also sound advice because humidity begets condensation. Condensation can lead to corrosion. And, even if you are good enough at DIY to install these new pipes yourself, having a professional do it will also increase your pipes’ lifespans.

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