How to Shut Off a Gas Water Heater

A homeowner guide from Drain Edge Rooter, a licensed plumbing company in Rialto, CA (C-36 #1078977). Open 24/7, call anytime: (909) 927-3194.

Safety first: if you smell gas, do not light anything, do not touch light switches or electrical devices, and do not try to find the leak. Leave the home right away, then call SoCalGas or 911 from outside. Always follow the instructions on the label on your water heater, and call a licensed plumber if you are unsure about any step.

Knowing how to shut off your gas water heater is useful in a lot of situations: a leaking tank, a plumbing repair, a long vacation, or before flushing sediment. Most gas tank water heaters have the same basic controls, but models differ, so always check the instructions on the label on your unit.

When and why to shut it off

The tank is leaking. Shutting off the water and gas limits damage and protects the heater.
You are flushing or draining the tank. The burner should not run on an empty or draining tank.
Repairs are being done on the water heater or nearby plumbing.
You are leaving for an extended trip. Many gas controls have a vacation setting that keeps the pilot lit but stops the burner from heating the tank.
The temperature and pressure relief valve is discharging or the heater is overheating, making unusual noises, or showing scorch marks.
After an earthquake, if you see damage to the heater, venting or gas line.

If you smell gas at any point, stop. Do not operate controls; leave the home and call SoCalGas or 911 from outside.

Know the parts before you start

Gas control valve (thermostat): the box on the front of the tank near the bottom, with a knob marked ON, OFF and PILOT, and usually a temperature dial. Some models have a vacation setting.
Gas supply shutoff valve: on the gas pipe leading to the heater. It usually has a lever handle. When the lever is parallel to the pipe, gas is on. When it is perpendicular (crosswise), gas is off.
Cold water supply valve: on the cold inlet pipe at the top of the tank. It may be a lever (ball valve) or a round handle (gate valve).
Power cord or switch: only on power-vent and some newer units that use a blower fan or electronic controls.

Step 1: Turn the gas control to OFF

Turn the knob on the gas control valve to OFF. On many models you need to push the knob in slightly while turning. This stops the burner and the pilot. If you only want to stop heating, for example while you are away, use PILOT or VACATION as the label describes.

Step 2: Close the gas supply valve

For repairs or a leaking tank, also close the gas supply shutoff on the line to the heater. Turn the lever a quarter turn so it is perpendicular to the pipe. Do not force a stuck valve with a wrench; that can damage the valve or the gas line. If the valve will not turn, leave it and call a plumber or the gas company.

Step 3: Shut off the cold water supply

Close the cold water supply valve on top of the tank. A lever valve turns a quarter turn so it is crosswise to the pipe. A round handle turns clockwise until it stops. This stops new water from flowing into the tank. If the tank is leaking badly and this valve will not close, shut off the main water valve to the house.

Step 4: Power-vent and electronic units

Power-vent water heaters use an electric blower to push exhaust out through plastic vent pipe, and many have electronic ignition instead of a standing pilot. On these units, after turning the gas control off, unplug the unit or turn off its switch or breaker. Leave the gas valve off and follow the label for any additional steps. Do not open the blower or electronic control housing.

Step 5: Relieve pressure and drain if needed

If you need to drain the tank, open a hot water faucet in the house to let air in, attach a hose to the drain valve, and let the water cool before draining when possible. Water in the tank can scald. See our guide on flushing a tank water heater for the full process.

Turning it back on

Close the drain valve if you opened it.
Open the cold water supply and leave a hot faucet open until water runs steadily without air. Never fire a water heater with an empty tank.
Open the gas supply valve.
Relight the pilot following the label, or for power-vent and electronic units, restore power and set the control to ON.
Set the temperature as the label recommends.

Our guide on lighting a water heater pilot walks through relighting step by step.

Seismic straps and venting

California water heaters are required to have seismic straps. While you are at the heater, check that the straps are secure, the vent pipe is connected and not rusted through, and nothing flammable is stored near the burner. If anything looks loose or damaged, have a plumber look at it before turning the heater back on.

When to call a pro

Call a licensed plumber if the gas supply valve is stuck or leaking, the tank is leaking from the body, the vent is damaged, you see scorch marks or soot, the relief valve keeps discharging, or you are not comfortable with any step. Drain Edge Rooter is open 24/7, so call anytime at (909) 927-3194. If you smell gas, leave first and call SoCalGas or 911.

Related services and areas

Related services: Water Heater Repair & Installation, Water Heater Repair in Rialto, Gas Line Repair. We serve the whole Inland Empire, including plumber in Rialto, plumber in Fontana, plumber in Ontario, plumber in Upland. Also see How to Flush a Tank Water Heater and all homeowner plumbing guides.