What's more, you can't make those major plumbing repairs or improvements unless you first turn off the water. The same goes for turning off the gas ... shutoff valve located after the meter (Photo 2).

Shut off the water at the main shutoff valve. If you have a gas water heater, turn the knob to the 'pilot' position. Shut off the circuit breakers to an electric water heater. Then open a faucet ...