Last updated: July 2026 · Reviewed against A.O. Smith and Rheem operating instructions
To turn off a water heater, you need to stop two things: the power or gas that heats the water, and the cold water flowing into the tank. The exact steps depend on whether you have a gas or electric unit. This takes about two minutes and is the first thing to do before any repair, or if you have a leak or emergency.
Quick Version
- Electric: switch off the water heater breaker in your electrical panel, then close the cold-water shutoff valve on top of the tank.
- Gas: turn the gas control dial to OFF (or PILOT to keep the pilot lit), then close the cold-water shutoff valve.
⚠️ If you smell gas at any point, stop. Do not touch switches. Leave the house and call your gas utility from outside.
Turning Off an Electric Water Heater
Electric water heaters run on a dedicated 240-volt circuit. Go to your main electrical panel and find the breaker labeled “Water Heater” (it is usually a double-width breaker). Flip it fully to OFF. If breakers are not labeled, the water heater breaker is typically one of the larger double breakers. Never try to turn off an electric heater at the unit itself — always use the breaker.
Turning Off a Gas Water Heater
Find the gas control valve near the bottom of the tank — a dial marked ON, OFF, and PILOT. For a full shutdown, turn it to OFF. If you are only doing quick maintenance and want to avoid relighting the pilot, turn it to PILOT instead, which keeps the pilot flame but stops the burner. For a complete shutoff, you can also close the gas supply valve on the gas line (handle perpendicular to the pipe = closed).
Shutting Off the Water Supply
The cold-water shutoff valve sits on the pipe entering the top of the tank — usually a lever or a round handle. Turn the lever a quarter turn (perpendicular to the pipe) or twist the round handle fully clockwise. If this valve is stuck or missing, shut off your home’s main water supply instead. Closing the water is essential if you are dealing with a leak from the bottom or from the top.
Should You Drain the Tank Too?
For most shutoffs, no — turning off power/gas and water is enough. Drain the tank only if you are replacing it, leaving the home unheated in freezing weather for a long period, or doing a repair that requires an empty tank. To drain, attach a hose to the drain valve at the base and open it (after shutting off the cold water supply).
FAQ
Should I turn off my water heater if it is leaking?
Yes. Shut off the power or gas and close the cold-water supply valve immediately. This stops the leak from worsening and removes the hazard of water reaching electrical or gas components while you diagnose the source.
Can I turn off just the water heater without the whole house?
Yes. The cold-water shutoff valve on top of the tank isolates just the heater. Only use your home’s main shutoff if that valve is stuck or missing.
Is it OK to turn off a water heater when on vacation?
Yes, and it saves energy. Gas units have a “vacation” setting on the dial; electric units can simply be switched off at the breaker. Just avoid leaving the tank drained and exposed to freezing temperatures.
Sources: U.S. Department of Energy — Water Heating · manufacturer service documentation (A.O. Smith, Rheem, Bradford White).