We don’t have a separate hot and cold connection like that, but we can shut the water off completely using a lever in the garage. It’s been done, especially when Bill was at home.
That’s odd. Water must flow into and out-of the heater. Does it just not have a shut-off valve? That would mean you have to shut of water to the entire house to do heater repair.
Maybe it would be worth a few bucks to put one in on the heater inflow.