Should You Turn off Water Heater if Water is off?

Water heaters are a tricky thing. They keep the water in your whole house hot, yet we don’t know much about them. For example, should you turn off your water heater if the water is off?

There is not much danger in leaving your water heater on when your water is off. Because tanks work through water pressure to supply the hot water, the tank pressure will be equal to your water pressure the whole time. If there is no inlet water pressure, there will be no outlet water pressure.

Just think about it, if shutting off your water and leaving your water heater would happen to cause some damage to your home, the water heater manufacturers would be buried in lawsuits every day. In case it somehow manages to cause any issues, all the parts of the machine, including the labor provision and costs, would be covered by the manufacturer.

Should you turn off the water heater if the water is off?

There is no right answer to whether you should turn off the water heater if your water is off. It all depends on the situation. We will consider some situations, but before that, we have to take into consideration the fact that all heaters were made to be as accident-free as possible.

The first situation is that your water tank is empty and you’re leaving for a long period of time. Most water heaters divide into two, which separates cold and hot water. There is also a dip tube on the cold water side that keeps the cold water at the bottom of the tank. If anything were to happen and the pressure is lost on the cold water side, the tank siphons down through the cold water inlet until it reaches the bottom of the dip tube. Then, considering there’s no more water in the tank that would absorb this heat, the dip tube could melt and the tank will end up getting damaged.

That being said, this is an extremely unlikely situation. This situation depends on the absence of water from your tank, which is completely unlikely. For this to happen, you would have to intentionally cut off the supply from the water tank.

So, in the situation where your water tank is empty or significantly lacking water, you should turn it off if your water is off.

In case your water heater tank is full, and the water will only be off for a short time there is very little to no risk involved. You can turn off the cold feed valve to make sure no water is siphoned out of the tank if cold water is also used with the tank off.

Keep in mind that that wouldn’t allow much of the hot water to be used out of the tank as this would have airlocked the system. However, you have to be aware that the water heater will still turn on and off to maintain the water temperature inside the tank, anyway.

In case you leave for a long period of time, there will be no water use for days, maybe even weeks, which doesn’t cause any problems with the tank. Even if someone had to use the water, most water heaters have low water cutoffs normally built into the unit roll. 

Your tank is also designed to avoid being “tricked” to constantly run in order to try and maintain temperature if all of the hot water in the tank is used up. This will also help avoid any possibility of a melting dip tube or a catastrophic failure of the tank.

You shouldn’t worry about turning off your water heater, as this design kind of does your job for you.

How do you shut the water off to your water heater?

Disconnect from the power source

The first thing you have to do is disconnect your water heater from its power source. If you have an electric unit, make sure you turn off the circuit breaker, and go to the dial close to the thermostat and move it in the other direction if you have a gas unit.

Turn off the water

Make sure the electricity connected to the water heater is turned off completely before you turn off the water. You will probably find a circular handle, and all you need do to turn it off is to twist it to the right. 

With that, you will open the way for cold water to flow in, and your sink and tubs will not get hot water. In case you can’t find where water is connected to the heater, turn off the water supply for the whole house. Find the valve close to the meter, open the box, and turn the valve in the other direction.

Drain the water in the tank

There should be a spot at the bottom of the tank where you can connect a hose to drain the water. Attach the end of the hose to a floor drain or a tub until all the hot water runs out. Make sure you read the product manual carefully to get any specific information about safety while draining water.

Label your circuit breaker

Your circuit breaker might seem complex and unclear. Because of that, you should label it. That way you will make sure you know the original position of each component. 

Should you turn off the water heater when on vacation?

Even though it might sound logical to turn off all your energy-using appliances while you’re out of the house, there are some good reasons why you should leave your water heater on while you’re on vacation.

If you live somewhere where it’s cold, you should keep in mind that your water heater keeps your water from freezing inside the pipes. Once water freezes in pipes, it can cause cracks, leaks, or totally destroyed and burst pipes. 

In case you’re going to be gone for a while, it is good to get a house sitter. It doesn’t matter if it’s someone who is going to water your plants and clean your house or just watch TV for a few hours every day. A potential robber is going to look for activity in the home, and if they see lights on and hear a noise, they’ll find someplace else to rob. Your house sitters will need to use the hot water to do some dishes, take a shower, or wash their hands. In this case, it is best to leave the water heater on so you don’t have to give your guest instructions on how to turn it on.

It is very often that something works just fine before you turn it off, and then it won’t turn on again. To avoid the risk of your water heater breaking, and you having to pay to get it fixed, just leave the water heater on while you’re on vacation.

If you turn off your water heater it will actually cost you more than if you had just left it on during your vacation. Keeping the water hot costs, but reheating cold, or even freezing water costs even more.

In case you aren’t someone who turns off their water heater regularly, it is highly likely that you will forget to turn it on when you come back home. It might even happen that you do a few loads of laundry before realizing that your water heater is off, which will double your work around the house.

If you really care about the cost of keeping your water heater so much, just turn your water heater’s temperature down to the lowest setting. This will keep the water from freezing, but you won’t waste any money on keeping your water piping hot.

Reasons for turning water heater off

There are many cases in which the main water supply is turned off. When this happens, many people don’t know if it’s safe to keep the water heater on of it should be shut down too.

In most cases, it won’t be necessary for you to turn off the water heater, but it also won’t hurt, either. Nevertheless, there are two cases when you should turn off the unit to prevent too much pressure or heat from building up inside the tank.

The first case is when your tank is empty, or close to empty, and you know that it’s not going to be refilled for a long period of time.

The second case is when the main water supply loses pressure. 

If your water heater starts leaking for any reason, including age and a valve malfunction, you should always turn it off, and shut off the water supply until the issue is fixed.

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