I had a newly installed system 200 furnace with hot water heater around a year ago. I recently noticed that there is a green residue peeling off the pipe going into the hot water heater. I called the plumber who installed it but have not heard back. Is this something i should be concerned with and if so is there a fix without calling out another plumber?

enter image description here

1 Answer 1


It looks like the copper joint was not sweated properly and is leaking. You'll want to get the plumber to pull the coroded pipe (the green is what copper corosion looks like) and sweat a new pipe in there

If you want a DIY solution

  1. Shut the water off
  2. get a pipe cutter and cut the pipe off just before the elbow
  3. Buy some Sharkbite push connectors and replace the coroded section with PEX. Will probably run you about $20 (not including the cutter)

Make certain the PEX and connectors are the same diameter, and that your water heater is not putting out water above 180 degrees

  • Agreed....leaky joint. The flaky white matter are salts precipitated from the leaked water. Green material is likely copper carbonates and sulfates, resulting from the reaction of water, copper, precipitated salts, and a little electricity to help run the chemical reaction. Jan 13, 2017 at 17:47
  • 2
    Depending on what codes rule where you are, you may not be able to use PEX to connect to the water heater. 2015 Uniform Plumbing Code 604.13 ... PEX... tubing shall not be installed within the first 18 inches (457 mm) of piping connected to a water heater.
    – Tester101
    Jan 13, 2017 at 19:33
  • 2
    SharkBite® makes a flexible water heater connector, they even have one with a built-in ball valve
    – Tester101
    Jan 13, 2017 at 19:35
  • I second @Tester101. The best solution is to use a flexible connection with a non-conducting connection, commonly called a dielectric coupling. These are either flexible metal or silicone with braided stainless armoring. Water heaters used to be sweated in hard all the way to the nipple on the tank, but this causes electrical conduction between the steel tank and the copper plumbing. This leads to corrosion of either the steel tank or the copper plumbing or both. Thirty-five years ago I installed a water heater this way (following the advice of the city code inspector) and it did not last. Jan 13, 2017 at 22:04

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.