I live in Texas and am dealing with a destroyed external tankless hot water heater. When I restore water to my house via the street valve I have water gushing out of the pipe below my hot water heater as it appears to have multiple cracks. I would like to at least use water to the rest of my house while I wait who knows how long for a plumber. What would be the easiest way to cap off this blue pipe or the pipe coming out of my house?

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2 Answers 2


Absent the presence of any valves...go to hardware store plumbing dept. And get a 3/4" sharkbite or tectite end stop. You just shove this on to the end of the (cut or removed) blue pex pipe. Get a 1/2" one in case I'm wrong judging size from the pic...be sure to buy the same size removal tool as well. It is cheap.

I keep these in my emergency preparedness kit...

If you post a pic of the top of this valve, we can help with temporary plumbing. Good luck with your recovery!


If the tankless heater was installed properly there will be a valve just before the heater to allow shutting off the cold water to the heater. My indoor tankess WH has a shutoff valve in the cold line and also has a valve on the hot water side. Double valves are recommended, but I believe that a valve on the cold inlet is required by code. Do you have these?

Is the valve in your current pic in the cold water inlet line or the hot water output line? Blue usually used for cold. The insulation on the other line might have been placed on the hot line. If the blue is the cold inlet, then that valve has shut off the cold inlet to the heater.

We need to see pics of the entire setup.

Where is this in Texas?

  • Thanks Jim for the reply. We are located in Austin and got hit hard by the recent snow storm. This is the cold inlet, I have it turned off at the unit, but it is leaking below it badly due to cracks from the cold. Finally found a plumber to come out tomorrow but I appreciate the help.
    – user130505
    Feb 21, 2021 at 1:27
  • It would be beneficial to others to document the repair with pics. Does your gas tankless WH have 120 vac powered controls? Did it have an internal heater? Did the heater itself freeze? I helped a neighbor here in Far North Dallas with an outside tankless with an internal electric heater. Feb 21, 2021 at 13:08
  • How did this situation resolve? Was the tankless WH wrecked by freezing? Feb 24, 2021 at 23:27
  • Hi Jim, amazing still waiting on our WH to be replaced due to difficulty getting a plumber out. We did have an emergency fix done to cut off the leaking below the valve. The plumber found a crack inside the unit so it did get destroyed.
    – user130505
    Mar 4, 2021 at 16:31

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