I need to replace my hot water tank as it's old and we run out of hot water fast. I actually did maintenance on it by shutting power off, cut off cold water and draining a bit of water from bottom drain as the maintenance manual says ro do every year, previous owner never did that, doubt many do.

Now the drain valve continuously drips and will not stop, super!

My questions however is that I can see the previous installer, plumber hopefully, added a hardening compound at the top of the cold and hot water. I can chip away at it, and it crumbles, but I do not know what this is and trying to unscrew with a wrench hard enough does not make them move at all. So I'm stuck. Here are images. Should I attempt with a bigger wrench to loosen these up, as the bond will break? or better off removing the pex piping by the metal rings that is holding the pex to the big screws. Sorry I do not know the name of these rings...

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  • Don't know enough about removing pex chimp rings, except from youtube. One type is soft and can be pried off, the other type need to cut the pipe(before the ring). The hard stuff should pipe sealing paste. Once the pipe is off then the fittings should unscrew. Use two wrenches, one to stop pipe from turning.
    – crip659
    Mar 9, 2022 at 0:52
  • Your drain valve probably drips because some sediment has gotten into valve area, or the washer has deteriorated, or both.
    – DaveM
    Mar 9, 2022 at 3:28
  • Have to wonder if you just have a bad lower element or thermostat. "Old" is not inherently a problem until leaking sets in, and "runs out of hot water fast" is either small tank or bad lower element. Anode rod, elements(s) and Thermostat(s) if needed, new drain valve, and an insulation over-wrap - still a lot cheaper than a new unit if this one isn't from the dark ages (doesn't look too old, probably has a manufacturing date on it someplace.) Or half the size you need, of course. Agreed that's probably just pipe dope, though I suppose a bad DIY with epoxy isn't out of the question.
    – Ecnerwal
    Mar 9, 2022 at 4:28
  • If you rotate the overpressure valve while gently opening and closing it may clear Mar 9, 2022 at 11:28
  • It's the drain valve that's leaking, not the overpressure - but the same approach of opening and closing it a few times might fix it. If not, easy enough to replace (with adequate wrench.)
    – Ecnerwal
    Mar 9, 2022 at 13:57

1 Answer 1


No reason to think that it is anything but old style pipe dope which contains calcium carbonate (white); it does harden to some degree. A bigger wrench may be needed, not pliers. The lower photo looks like another problem , it looks cross-threaded. Apparently by forcing it enough with plenty of dope has made it up enough not to leak. It may need an even bigger wrench. The galvanized steel nipple of the heater was able to cut into the brass fitting and has little damage. There will be a new nipple on the new water heater. I would plan to replace the brass fitting. However, the dope hides enough of the threads that I cannot be certain it is cross-threaded

  • Thanks @blacksmith37, once I have the new tank ready, I'll be hacking at it with a bigger wrench to get them to turn. Should I put more pipe dope or whatever they call it as the store for the new install? I really hope those fitting will release with no damage for the next tank
    – gstlouis
    Mar 9, 2022 at 15:41
  • All (normal) pipe threads (i.e. this sort on water pipes, not compression fittings or threaded fuel pipes) need tape or dope, and I have had better luck with dope, overall. So yes, new dope for the new threaded connections. Or teflon tape if you wanna go that way.
    – Ecnerwal
    Mar 9, 2022 at 16:04
  • so this is done. Thanks for the inf. It was Teflon liquid apparently? Didn't know that existed. The new tank is on with good old Teflon tape, less messy, and everything is good. cheers
    – gstlouis
    Mar 14, 2022 at 18:18

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