We're doing a kitchen demo and changing where the dishwasher is going to be, so Step 1 is to disconnect the dishwasher (3 connections: electrical, drain and water supply).

I have already taken care of the electrical and the drain.

I found the hot water supply line down in the basement which feeds the dishwasher with hot/warm water. I turn the (very corroded) gate valve off as far as I could and cut the copper pipe. I noticed water was still trickling out of it (very slowly) about 15 minutes later, and so I tightened the valve even more (as much as I feel comfortable doing) and its still leaking by a little bit. So I bought a 3/8" Sharkbite endcap and popped it on the end of the pipe, where I had cut. Leaking stopped, figured I was all good.

This morning I go down to the basement and sure enough, it looks like there is a slow leak coming out of the valve now (but not at the end cap), So I'm guessing there's a leak at the valve and now enough pressure has built up in the line (since I capped it) to force the water to leak out of the valve. So I think its time to replace the valve. I just want to use Sharkbites and a new ball valve.

My understanding of the process here is:

  1. Kill power to my hot water tank
  2. Between my hot water tank and the leaky valve, find the next upstream-most valve that is not leaking and turn it off (we'll call this the "Feeder Valve"); this will kill the water supply to the leaking valve
  3. Cut the valve out and drain the water
  4. Install the new ball valve, installing it in the closed/off position
  5. Turn the Feeder Valve on
  6. Turn power back on to my hot water tank
  7. Slowly, turn the ball valve that I just install back on and let it blow out any air and fill the line with water (draining it as needed) and then close it

So to begin with, if anything I've said above about the overall process seems wrong or misled or out of order, please begin by correcting me!

Assuming I'm more or less correct, here's my issue.

There really aren't any "Feeder Valves" in between my hot water tank and my leaky valve, except for the valve that is coming out of the hot water tank itself:

enter image description here

The left pipe (that's wrapped in insulation) is hot water coming out of the tank. That pipe splits several times, and one of the "branches" goes right to the leaky valve, some 30 ft later.

So my question: given everything I've said, am I going to do any damage or cause myself any headaches by just treating that valve in the photo as my Feeder Valve, and turning it off before I cut out the leaky valve?

I guess my concern is that with that valve turned off, once I cut my leaky valve out, the water from the other pipes branching off are going to try and drain through where I make my cut. I guess I'm also worried about turning that valve off so close to the tank and possibly damaging my tank or turning it into a pressure cooker somehow.

Any advice or steering here? Thanks in advance!

  • 2
    Wow! I've never seen so many crimp fittings on a water heater.. :-)
    – JACK
    Mar 26, 2023 at 15:16
  • 1
    When I was a kid, they told me I could be anything... Mar 26, 2023 at 16:04
  • Watch any of the 4 or 5 Mythbuster's episodes on exploding hot water heaters. They have to disable multiple safeties in order to get the heaters to explode. Can a HWH explode? Yes. Is it easy to make it happen? No
    – FreeMan
    Mar 27, 2023 at 16:57

1 Answer 1


You aren't going to hurt the water heater by turning off the hot water outlet, that's what it's for. That pipe in the middle is your pressure relief if anything did happen. As far as water draining from your cut, open any hot water fixtures on the top floors to let air in and the system will drain niceley.

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