Leaving a Water Heater on with Water Off, Plumbers Respond

turn the heaters off

It is common to wonder when we are supposed to turn off the water heater.  Just like when we turn off all the things in the house when not in use. Different people have different views on the same things. This is why we asked some local plumbers on their point of view, because they let’s face it, they have more experience. The questions asked several plumbers was…should I leave my water heater on with the water off?

Yes, if the water is off, it means there is no water flow, so a tankless heater will not run. A tank style heater will maintain the tanks temperature heat setting, but can be reduced for vacations. Present water leaks would be the only time to turn water off, and the heater off for safety.  

So now, let’s dig it the the reasoning behind their overall answer…

When You Should Turn Off the Water?

There are different scenarios, which present themselves that may lead you to turn off your water heater.

turn the heaters off

When the Water Heater Leaks

If this happens to be the scenario for you, it is advised that you turn off the water through the valve on the heater to minimize leakage. But if the valve is broken, turn off the water supply. The reasons that may lead to this are:

  • When there is too much pressure as a result of very high temperature or pressure of the exterior water coming into the tank
  • When you have a damaged tank
  • Due to an improper drainage
  • The “end-of -life” life span of the water heater
  • When There Is Water Shortage

If you have water leaking for more than 24 hours, ensure that the heater is off. Electric tank water heaters have two elements: the top and bottom. When the water drains down, it means that the top element is exposed, making it too hot. When this happens, it shorts out, rendering the element useless, meaning money that would be saved is now given to a plumber.

What effects or damage could happen leaving your hot water heater on with the water off? Check this article

When Turning Off the Water Heater Doesn’t Matter

During a Vacation

The new version of water heaters have the option of turning the thermostat down or to vacation mode. When you choose either of the two modes, you lower the amount of electricity that will be consumed in your absence. These options lower the temperature to 50F unlike on normal conditions when it reads 120 to 130F. The water will be kept warm so that when you return, there is no usage of high electricity when heating the water, considering it will heat within a duration of 20 to 40 minutes, maybe up to an hour depending on the heater you have.

I personally, just chunk it back a smidge to 80 – 100 degrees. This way I can at least take a shower when first home, and then I can crank it up to the proper setting. (this is basically because I forget to turn it back before my shower)  Also, this is only when gone over a week.

You can also insulate your hot water heater tank and save 7% to 16% annually. Insulating the tanks means that the amount of heat lost to the environment is greatly lowered, hence the savings. Check the one we recommend out on Amazon by clicking here.

During Normal Operations When the Tank Is Full

When you are around the house every other day, there is no need to turn off the heater unless it’s for the above mentioned reasons.

The water temperature will not drop that fast inside the tank, especially an insulated tank.

Expert Advice

Turning off the water heater doesn’t really have an important role as many people would expect. This is because:

turning tankless water heater

The amount saved when turning off/on the water heater is insignificant.

You will only save cents in a day depending on the model that you use. The fact is that you pay for the water heater to be heated, and that’s why you pay the bill.

You create more problems by turning off the water heater between uses and back on within short periods of time.

Also, when you turn off your water heater when on a vacation, you only meet more problems. The guaranteed issue will be that your water heater will take a long time to heat the tank water back up. Some units, there will be difficulties to turn it on again, lighting a pilot light comes to mind for gas powered water heaters.

Install Timers.

There are timers that automatically turn on/off the water heater depending on the need at hand. Timers turn off the electric heater during long spans of time such as during the night or when the house is unoccupied.  This doesn’t really help save unless you have special rates at certain times of the day or you have too much demand at certain times of the day.

With the timer you can set the timer to make sure you are off in demand times, and on during lower kilowatt cost.

Drain Your Tank.

This is accomplished by opening the valve at the bottom of the tank. When you drain the tank, you get rid of any residue or sludge out of the bottom part of the tank. It helps on gas heaters with the time taken to heat the water.  On electric tank heaters it improves the volume of water, in other words more hot water to use.

Final Thoughts

Everyone has their opinion on what they feel should be done under any circumstance. At the end of the day, you have to make the choice yourself of whether to turn on/off the water heater and when to do it. Take the option that gives you the most comfort, it is your peace of mind.


David: Penn State-educated Mechanical Engineer and Business-savvy Fluid Dynamics Specialist. Balances family plumbing business support with a thriving engineering career at a top, undisclosed company. (they want it that way) I help Will with plumbing and HVAC needs on his Real Estate.

Check these out....