Hello recently my old 50gal gas water heater developed a crack and started leaking. I replaced it with a tank-less gas heater. Everything is good, I installed the proper intake an exhaust with 3in schedule 40 PVC pipes as recommended, I plumbed 3/4in copper pipes for cold and hot water, a 3/4in gas line. I now need to connect the pressure release valve. I have a 3/4in copper pipe plumbed into the house drain close by, so it does not look to be a big deal, however, this unit also has a condensate drain. Right now I have a temporary 1/2in PVC discharge into a bowl, but I plan to install a condensate neutralizer (it's arriving tomorrow). However where am I going to drain the neutralized water? Can I plumb it with the relief valve? Eventually it will have to go in the drain anyway. The unit is installed in the center of the house upstairs in an utility room.

Current plumbing work in progress

  • You can not use the plumbing for the relief valve to drain the condensate they can go to the same location but cannot use the same pipe. If you have plastic drain lines I would not worry about a neutrilizing the water as these fail and have issues that you may not realize on metal drains they can reduce the ion leaching but need to be checked regularly.
    – Ed Beal
    Commented Feb 21, 2019 at 14:45
  • This is where I am confused. The drain system of the house will eventually be "the same pipe" as there is only one connection to the public sewer line. When, what kind of piping to I need to make it not "the same pipe"? The drain lines in my house are copper and then they become cast iron at some point (who knows what is original from the 70's and what has been remodeled before I bought it). Just after the house there is a clay line that goes into the public sewer. Commented Feb 21, 2019 at 19:44
  • In some locations neutralizers are a code requirement to protect the environment and municipal waste systems but it's rarely enforced.
    – Joe Fala
    Commented Feb 21, 2019 at 20:25
  • As I have stated I have a neutralizer in any case, so that is not really up for debate. I just need to find out how to plumb the output of the neutralizer. Commented Feb 21, 2019 at 21:00
  • I understand they go to the same place but tapping the relief is a no no.
    – Ed Beal
    Commented Feb 22, 2019 at 0:56

1 Answer 1


Yes down the drain is good, the condensate is slightly acidic, usually in the 3-5 pH range. The neutralizer is supposed to, well, neutralize it back up to 7 pH but they do wear out or clog. Make sure your condensate doesn't come into contact with metals. It will eat them. Do yourself a favor and always pipe in your neutralizer like this in case it blocks up it can bypass. I always use Clear gorilla tube to allow for visual inspection.https://www.diversitech.com/en-US/item/id/11672 enter image description here Make sure you pipe your pressure relief valve down to within 6" of the floor and not into the drain maintaining 3/4 inch diameter all the way. In the rare event that it pops you are supposed to see the water on the floor and thus be alerted to the issue. If it's down the drain you will never know you have an issue. https://www.google.com/aclk?sa=L&ai=DChcSEwjZsrDb78zgAhUOtrMKHQFmBB8YABAIGgJxbg&sig=AOD64_3f3Fc_0mYzjmXXWbHAYQvAGUPvyw&ctype=5&q=&ved=2ahUKEwiJ5abb78zgAhWCZd8KHSvbAk0Qwg96BAgLEBA&adurl= this one is 50 bucks enter image description here

  • I see. The old water heater was hard plumbed (solder connections) to the drain line that is inside the wall, behind the sheetrock. Now I need to figure out the best solution. Commented Feb 21, 2019 at 7:15
  • You could use a condensate pump, they should be available for under a hundred bucks. I'll add a link to my answer.
    – Joe Fala
    Commented Feb 21, 2019 at 12:54
  • But what would be the value added by a pump that I cannot get with gravity alone in this case? I must be missing something obvious :( Commented Feb 21, 2019 at 19:47
  • If all the drains in your house are copper or cast-iron you'll have to be careful where you pipe the condensate to. Ideally you would be able to pipe it somewhere where there isn't any metal piping but if that's not an option you can use a condensate pump to, pump outside if you're in a climate where you don't experience freezing temperatures. If that's not an option you'll definitely want to maintain your neutralizer and perhaps test the condensate with pH test strips from time to time and simply pipe it to the closest floor drain.
    – Joe Fala
    Commented Feb 21, 2019 at 20:22
  • Yes I have a PH-meter. A condensate line that goes out would be tens of feet long and I would have to tear down half of the house to run it :( Commented Feb 21, 2019 at 21:02

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