Is this my main water shut off?

[oakley_kobe]

I know this is probably a really dumb question, but my builder is unresponsive and the plumber is also not responding to any of my calls. I’m just trying to verify if this is my main water shut off valve. It’s located right next to my water heater In the garage.

I turned it to the off position, but water still seems to be running out of faucets, although at a much lower pressure.

If this is the main water shut off, is the water coming in from the pipe on the bottom, then out through the top pipe?

Thanks!

 

[breplum]

I've frankly never seen such a location for an expansion tank, but yes, that seems like it should be the indoor main shut-off.
The installation is odd for a few reasons, #1: expansion tank is not needed on systems where there is no check valve to create a closed system.

That Watts N45B as per the mfr: "• Bypass feature controls thermal expansion pressure*** meaning there is no built in check valve.
But maybe your water provider does have a check valve on the meter, but that is somewhat unusual.

obviously you may need to shut down at the main outside

 

[GReynolds929]

Looks like a main shut off valve, a pressure reducing valve, and a thermal expansion tank. Water comes in from the bottom. The main shut off valve is currently on in the pictures shown. The PRV looks like it may be set to a very low pressure as the adjustment bolt looks like it is backed out quite a bit. Maybe it's the angle of the picture but the pump and piping on your water heater look odd.