The water line coming in from the street is often connected to the water meter followed by a master shut-off valve for the entire home. Close this one valve and you have shut off water throughout the house – it’s instant action for serious emergencies.
If you need to shut off the water at the main valve, make sure the hot water tank is turned down to pilot. If you have a hot water heating system you will also need to make sure the furnace has a sufficient supply of water. (This should be checked often.)
Electrical hot water tanks require special attention; and it is best top enlist the aid of a plumbing and heating professional.
However, if the emergency calls for the main water system to be shut off, the electric water heater must also be shut off at the main electrical fuse box by either removing the fuse from the box or switching the breaker to an “off” position.
The electricity to the hot water tank should not be turned on until the water tank has been refilled with water – see the owner’s manual that comes with the electric hot water heater.