Plumbing, Water Heaters

How to Turn Your Water Heater Off

Updated on

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There are some scenarios where you may want to turn your water heater off. Maybe you’re leaving a vacation home, or if you are experiencing technical problems with your water heater, you will need to switch it off, perform the necessary repairs, and then switch it back on.

It’s a good idea to be familiar with how to turn off your water heater. You’ll need to turn the thermocouple knob off and close the gas valve in a gas water heater. In an electric water heater, you’ll need to turn the service disconnect or circuit breaker off.  

This article will look at the steps involved in switching off both the gas and electric water heaters. We will also enlighten you on when it is okay to switch off the water heater and other related questions. Keep reading to learn more.

How to Turn Off a Gas Water Heater

If you have a gas water heater in your household, ensure that the water pipes drain well. Allow the water to cool down for some time if you’ve utilized it. As soon as it cools down, switch off the tank’s cold water supply to ensure no water gets in. To get optimum results, follow the steps below.

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Locate the Thermocouple and the Knob to Off

If you inspect the front part of the tank, you will see the thermocouple with a black or red knob. Rotate or move the knob from the “on” to the “off” position.

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Locate and Turn Off the Gas Supply

The main gas line to the water heater thermocouple should have a gas shut-off valve. Turn the valve perpendicular to the gas line to shut off the gas to the water heater.

If you have a gas tankless water heater, you’ll need to turn the breaker off in the panel box and turn off the gas valve. Tankless water heaters have an electronic ignition system. Locate and turn the water heater breaker off.

How to Turn Off an Electric Water Heater

An electric water heater is relatively similar to a gas water heater in many ways. Nonetheless, there are a couple of steps to follow because the mechanism is distinct. Here are the steps to follow when switching off your electric water heater. 


Turn Off the Circuit Breaker

The first thing you need to do is switch off an electric water heater by finding the two-pole circuit breaker. Usually, it’s marked between 30 and 50 amps. 

Even if you’ve turned off the water heater, switch off the power at the circuit breaker panel. If your circuit breaker comes with lock-out lugs, attach them to it. 

Some water heaters have a service disconnect box close to the water heater. You can also turn off the power to the water heater at the service disconnect.

If you have an electric tankless water heater, you’ll likely have multiple breakers that will need to be turned off to fully shut down the electric tankless water heater.

When Turning off Your Water Heater, You May Need to Drain It

Depending on why you’re shutting off the water heater, you may need to drain it. If you plan to work on the water heater, you’ll need to at least partially drain it. When leaving your household in winter, make should empty the water in the tank if there’s a risk it could freeze.

To drain the water heater, you’ll need to:

  1. Shut off the cold water supply on the cold water inlet pipe.
  2. Connect a water hose to the drain located at the bottom of the water heater.
  3. Run the hose to the exterior of the home so it can discharge into a safe location.
  4. Open the drain valve to allow the water to exit the tank through the hose.

For instructions on draining your water heater see Water Heater Maintenance Tips to 2X Your Tanks Lifespan.

Is it Okay to Turn a Water Heater Off?

It’s recommended that you switch on the water heater before you need it if it comes with an on/off disconnect button. It gives the appliance time to heat your water. Irrespective of whether the water heater remains switched on when taking a shower or switched off, you can run out of sultry water.

Can you Turn a Water Heater Off and Leave the Water on?

The water heater switches on and off to maintain the temperature of water in the tank. Leaving the water on when the water heater is off isn’t risky. It’s because the tank works with water pressure to give hot water. The tank’s pressure corresponds to your water pressure. 

Turning off a water heater only saves energy. It doesn’t protect against a water leak. You could still develop a leak and suffer flooding damage if a pipe freezes or ruptures. If you don’t want to drain the water heater, you can shut off the main water supply to remove the water pressure from the water lines.

When Should I Turn a Water Heater Off?

Switch off a water heater if the principal water supply is turned off. 

There are two reasons for doing this: 

  • Switching off the water heater ensures that excess heat or pressure doesn’t accumulate inside the tank.
  • The tank is devoid and won’t be filled again because the principal water supply is losing pressure. 

Can you Switch Off Water When you’re away?

Switching off your water heater isn’t recommended. However, you can save a considerable amount of energy – and cash – if you’re on holiday by turning your water heater into vacation mode. If you’ll be out in winter, ensure you flush your lavatories to empty the water of the tanks. 

Is it Advisable to Leave the Water Heater Switched on Always?

Instead of switching it on and off, it’s advisable to always leave the water heater on. Your boiler or immersion heater heats the sultry water in your tank. Provided the tank has an excellent insulating jacket, it ensures that your water remains hot throughout the day, and, therefore, you don’t have to keep reheating it. 

Should I Switch Off the Gas Water Heater if Water is Shut off?

If you switch off water for a long time, it can cause severe damage if you use your sultry water excessively. Ensure you switch off your water heater if the water is turned off. However, do this if your water is switched off for a prolonged period, such as a holiday. 

How Long Should You Allow Water to Run after Switching Off?

If you switch off the water, you have to flush your pipes for half an hour to guarantee safety. If water remains stagnant in the pipes, it may have copper, lead, or other impurities that are unsafe for cooking or drinking. 


As a homeowner, there are several signs to look out for about water heaters. Your appliance may be making unusual noises or doing anything strange. 

If you observe any of these signs, switch off your water heater. Additionally, if there is a gas smell in your household, these are indications that you should switch it off. By leaving it switched on, the issue may worsen. We hope that now you know how to switch your water heater off. It’ll help you avoid problems in the future. 

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Hubert Miles

I've been conducting professional home inspections since 2002. I'm a licensed Home Inspector, Certified Professional Inspector (CPI), Certified Master Inspector (CMI), and FHA 203k Consultant. I started to help people better understand the home inspection process and answer questions about homeownership and home maintenance.
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