Help?! Late night water expansion tank leak

[-Wims-]

I just went down to my basement before bed and found that my "potable water expansion tank" is leaking. Pretty sure it's the tank itself leaking and not fittings; I can see a spray out of one side of the tank and there's an actual leak out of the bottom.

I know nothing about plumbing. I am not sure which valves I should be turning off -- the line to the tank from the hot water heater and the cold water TO the hot water heater? Then turn off the water heater itself? It's 12:45 at night here and it'll have to wait 'til tomorrow (or whenever I can get a plumber) to fix it.

 

[Reach4]

I know nothing about plumbing. I am not sure which valves I should be turning off -- the line to the tank from the hot water heater and the cold water TO the hot water heater?

You have both? I would just turn off the valve to the tank. Slowly dribble cold water from a faucet for 30 minutes after you take a shower or otherwise use much hot water. That will hold you until you swap the tank.

If you only have the valve to the WH and the leaky tank is downstream of that valve, close that valve, and turn the WH to Off or Vacation. Do without hot water for a bit.

 

[Sponsor]

 

[-Wims-]

Thank you! (And bless you for being awake!) Yes, it looks like there are valves on both the line to the HW tank and out of it toward the leaky tank. The valve on the left is the line into the HW tank, I think. And the one on the right goes out toward the leaking expansion tank.

 

[-Wims-]

This is a better view of the line toward the tank. In theory, if I close this valve, the tank will stop leaking when it runs out of water, right? Hopefully?

 

[-Wims-]

And nevermind. I figured out that valve is on the wrong side of the water flow so I was actually making it worse; I am really bad at this sort of thing! There wasn't a shut-off valve before the leaking tank (the pipe went straight from where it came into the house to that tank) so I had to shut off the whole-house valve. It seems to be slowing down now. Crossing fingers that fixes it until I can get a plumber in.

 

[Reach4]

The higher valve with the red knob, on the black pipe , that you show is for the gas. If you turn that off, you will probably have to re-light the pilot light. The one on the right with the yellow handle is the cold water on the way to the water heater. Shutting off that valve, as shown in the photo, stopped new water getting into the water heater. If you had connected a garden hose to the drain valve on the water heater, and run the water to a floor drain, the leaking onto the floor would have slowed or stopped.

The "potable water expansion tank" you refer to...I had thought you had a thermal expansion tank. I am now suspecting that you may have been referring to the water heater (WH). Or maybe you were referring to something that is not in your photos.

You don't see a thermal expansion tank in your pictures, and there is a good chance that you don't have one. So my comments were not relevant. You may get one of those as part of the new WH installation.

 

[-Wims-]

Thanks. The expansion tank is up on the ceiling in the top right of the second photo. I wasn't referring to the water heater itself. What you said makes sense, but it was easier at 2 a.m. with water raining everywhere down on me from the expansion tank to just shut off the water at the house level. The plumber's here now - I managed to get someone here more quickly than I'd have imagined -- and he's replacing the expansion tank so this emergency is over. Thank you so much for responding to my panicked post!