Should I Turn Off My Tankless Water Heater If The Water Is Off?

Ossiana Tepfenhart
by Ossiana Tepfenhart

If you take a look at most of our plumbing guides, you’ll notice that one of the first instructions we add involves shutting off the water. It’s simple, right? Well, sometimes you might want to think twice. You might want to know if your water heater needs to be shut off too. This is doubly true if you own a tankless system. After all, it’s important to do it all the right way, right?

Tankless water heater systems do not require you to shut them off if the water is being turned off. This is because they’re not made to run heat continuously. If there is no water in their heating area, they will not have any heat dispersed. The only time that you should turn off the heater is if you will not be using any water for days or weeks at a time, since leaving it on can harm your system long-term.

Doing a plumbing job correctly means knowing how to keep your water heater safe while you do repairs. Our guide will help you understand the basics here.

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Why Is It Okay To Leave A Tankless Water Heater On If I’m Doing Repairs To My Plumbing?

Tankless water systems do not hold any water in them by default. This means that you don’t run the risk of having leaks to your water heater system if you’re doing repairs nearby. Moreover, you also don’t have to worry about water overheating inside the tanks since they are designed to conserve energy. No water demand means no energy will be used while you’re working. It’s safe!

Because your tankless system already shuts off when no water is present, the system (kind of) already does this task for you. Doing it twice is just a bit redundant, don’t you think?

How Long Can You Leave A Tankless Water System On?

Technically, they can be left on indefinitely as long as you monitor them and are willing to use some water from time to time. That’s why you don’t see water heater controls out in the open. With that said, some people prefer smart water heaters simply because they maximize energy use efficiency and are easy to turn off while you’re out.

Should You Leave Your Tankless Water Heater On If You Go On Vacation?

Here’s the thing that many people get conflated: leaving your water heater on during a repair is not the same thing as leaving it on during your vacation. Repairs are short-term. You’re going to be in your home, looking at the water heater. Most repairs will take a couple of hours, so you will be ready to use your water again by the end of the day.

If you’re on vacation, you are not going to be there. Moreover, you are going to be gone for days or weeks at a time. While your tankless water heater might not contain any water to store, that doesn’t mean you’re scot-free. Leaks can still happen. If you leave it on, then you run the risk of having a leak occur in your home without any way to notice it or stop it. That can cause serious damage to your home.

How Can You Protect Your Home’s Water Heater While You’re On Vacation?

The best thing that you can do to prevent flooding and damage to your home is to shut off both the water and the water heater. This is the best way to prevent a flood while you’re out. However, you have other options you can consider:

  • Getting a smart water heater. Smart water heaters often come with sensors that can tell when you got a leak. These can allow you to call for a repairman while you’re out and also shut down the heater when you’re nowhere nearby.
  • Getting a housesitter. Nothing is easier than hiring someone to keep up your home and keep an eye on things. If things go awry, your housesitter can call a repairman.
  • Not shutting off the water or water heater. While this is not ideal and can increase the risk of a flood, people still do it. It’s just not a smart idea. Most of the time, nothing bad will happen if you have a tankless system. However, if you’re unlucky and a leak springs, you will have a ton of cleanup to do.

Related Questions

Does shutting off your water heater damage it?

Shutting off a water heater does not do any damage to it, so you should never feel worried about giving your heater a break. However, if you leave your heater unused for exceptionally long periods of time (years or several months), you may have a rough restart when you finally turn it back on. Sometimes, you might even have rust.To avoid extensive damage during long shutoff periods, the best thing you can do is shut down your water line and your water heater. With that said, you should try to avoid leaving your home’s water system unused for years at a time.

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Why should you get a tankless water heater?

Tankless water heaters produce endless supplies of hot water without requiring too much space. They are more environmentally friendly and also happen to last longer than a typical traditional hot water heater. Most people find them to be a highly efficient, low-maintenance way to get the hot water they need without having to deal with unusually high energy bills.

Is one tankless water heater enough for a household?

It can be. Small households that use 40 gallons or so per day can do well with one. If your home uses over 100 gallons per day, then you may need to get two tankless systems in order to be able to get the appropriate amount of hot water throughout the day.

With that said, some tankless models are now capable of handling heavy household demands. This includes demands for multi-family units. So it’s better to ask someone who has knowledge in specific models what their capability can be.

Ossiana Tepfenhart
Ossiana Tepfenhart

Ossiana Tepfenhart is an expert writer, focusing on interior design and general home tips. Writing is her life, and it's what she does best. Her interests include art and real estate investments.

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