The drain pipe under my sink is made of copper and has a couple of small holes just before it goes into the wall (and eventually leads out to a greywater tank). The picture below is taken from beneath the pipe showing it entering the wall which I had slightly broken into during my investigation.

Holey pipe

The copper feels thin.

Since the water isn't under much pressure, is there an easy way to repair the holes? It's a pain working under the sink, and I'd rather not break any further into the wall if I can avoid it.

  • Drainwater etches away copper pipe from the inside. How old is this pipe? The current holes may be the start of continual problems.
    – Bryce
    May 17, 2012 at 7:12
  • replace, not repair for this or you will see more leaks May 17, 2012 at 16:57
  • @Mark Schultheiss, why do you think there will be more leaks? Is waste water from the sink really so corrosive? Perhaps the pipe was bumped from underneath. May 17, 2012 at 17:41
  • 1
    If it was "bumped" and not with something substantial, it seems that it is pretty thin/weak - which weakness happens from the inside. If you "know" it was hit and how and feel comfortable with that impact being substantial it could be repaired. Corrosion of copper in a drain is higher than the source due to higher air saturation and lower pH due to alkaline substances (soap) and/or the presence of nitrates and sulfates. May 17, 2012 at 18:20
  • 1
    Oh, one note - ammonia in cleaners are particularly corrosive to copper. May 17, 2012 at 18:28

2 Answers 2


As Ryan said you can solder it (either with soft solder or silver solder use flux will make your life easier to) or you can just use a rubber repair on it either buying a propritory type or just making it your self out of a piece of rubber and a couple of hose clamps.

This is a plumb-quik from Fernco Fernco coupling

Keep in mind that you don't have to use the whole thing you can cut it open so it is easy to slide over the pipe and put the cut at the top of the copper pipe then put your hose clamps on and tighten it up . I've used this technique to repair a 6" stormwater pipe that was cracked and was a pressurized pipe with no problem.

Another easy way is to use Ferropre or similar a two part epoxy that sets like a rock and sticks to pretty much anything

If you are going to use Ferropre put on disposable gloves, get a bucket of water and mix the two parts together in the water it makes it much easier to handle as it doesn't stick to your gloves as much then once mixed just smear it over the holes in the pipe.



You can solder it using a lead free solder, Just make sure you scrub that pipe with sandpaper to clean the gunk/crap off or the solder wont stick.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.