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Should You Drain a Water Heater When Not in Use?

Fact checked by Stephen Conklin

should you drain a water heater when not in use

Many first-time water heater owners ask, should you drain a water heater when not in use? And although experienced users might laugh, it is a concern that deserves attention.

Our short answer to this is yes. However, there are instances beyond routine maintenance when draining the water heater is not required.

Keep reading to learn when it is a must to drain a water heater tank and when it is unnecessary.

Table of Contents

Should I Drain My Water Heater?


Yes, draining your water heater is essential to keep it in optimum working condition. However, it is worth noting that you’ll need to flush this household appliance after draining it.

This is because draining only empties the tank. You need to flush it to remove particles that might have accumulated at the tank’s bottom. Otherwise, the built-up sediments can still cause the heater to malfunction.

So, when should you drain your water heater? And are there instances when it is not necessary to empty it?

1. When Should I Drain My Water Heater?

It is sound advice to empty a hot water heater and turn off the central water shutoff valve when on vacation. If you must leave home for several weeks in the winter, draining the water heater is crucial to prevent it from freezing, which can burst the pipes.

Other than that, you’ll need to flush an old water heater at least once a year as part of routine maintenance. This benchmark can decrease if you live in places with high sediment and mineral concentrations. As such, if yours has been in use for a long time, it’s best to drain it, even if you don’t plan on relying on it for a long time.

It is also worth noting that water heater brands have draining and flushing frequency recommendations. For example, Rheem advises owners to drain electric water heater Rheem units annually, while A.O. Smith recommends a draining frequency of every six months.

Another reason for draining a water heater is when you notice the telltale signs of sediment buildup, such as hissing, popping, or rumbling sounds. When this happens, you might want to drain water heater sediment and other particulates earlier than scheduled.

2. When Is Draining My Water Heater Not Necessary?

You do not need to drain a gas water heater or an electric version when you only don’t use it for only a few days (i.e., less than two weeks).

For example, a three-day vacation means you will still use the water heater on the fourth day. Emptying is easy, but refilling the tank and heating the water can be a lengthy wait.

Why Should I Drain My Water Heater?


Draining your water heater and flushing it afterward is one of the most effective ways to ensure the appliance’s longevity. So, how does draining the water heater periodically (at least every six months) ensure its longer lifespan?

First, draining and flushing the water heater removes sediments, particles, dirt, and other objects in the tank’s bottom. These particles are not an issue if you have a water filtration system screening the water before it enters the water heater. However, without one, sediments can clog the heater and plumbing network, causing them to fail.

Second, minerals can also accumulate on the water heater’s inside surfaces and components, producing limescale. This buildup can also impact your heater’s performance.

Third, sediment or limescale-related water heater malfunction can be costly to fix. You might end up buying a brand-new unit if the existing one is beyond repair.

So, draining the water heater is crucial. But do you know how to properly drain a water heater?

Steps to Drain a Water Heater When Not in Use


Here are the steps on how to drain your water heater when not in use.

  • Step 1. Cut off the power and water supply to the water heater. Please do not drain your water heater without turning off the circuit breaker (if you have an electric water heater) or the gas shutoff valve (for gas water heaters).
    That said, you should check your user manual because some gas water heaters only require turning off the thermostat or adjusting it to Pilot.
  • Step 2. Wait a few hours for the water to cool. We recommend doing this step at night, so you can drain the water the following day without any issues.
  • Step 3. Get a garden hose and connect one end to the heater’s drain valve. Place the flexible tube’s other end on a floor or large bucket. You can also extend it to the yard if it is long enough.
  • Step 4. Go to the nearest hot water faucet and turn it on to remove pressure from the plumbing system and the heater. This step can also drain the appliance a lot more quickly.
  • Step 5. Rotate the heater’s drain valve to open and start draining the water. Watch the effluent for sediment, debris, and other particles. Be patient.
  • Step 6. Open the cold water inlet valve to flush any remaining sediments from the tank. Repeat Steps 5 and 6 until you notice the water flowing out of the garden hose already looks clear and clean.
  • Step 7. Close the heater’s drain valve and disconnect the garden hose. Turn off the hot water faucet and refill the heater’s storage tank with water. Restore power (electricity or gas) to the unit once the tank is full.

Frequently Asked Questions

What happens if you don’t drain your water heater?

Not emptying hot water heater tanks can cause sediments, particulates, rust, and other substances to accumulate at the tank’s bottom. Minerals can also form limescale, impacting the water heater’s performance.

Corrosion can result, and damage to the water heater’s heating elements can occur. You will end up with a poorly-functioning unit, necessitating a replacement.

How long can water sit in a water heater?

Water can sit in the heater for no more than two weeks. Otherwise, homeowners risk exposing their water heaters to hydrogen gas formation and buildup.

Although water does not deteriorate in quality or “go bad,” the water in the heater’s storage tank might be a different story. Chemical reactions in the unit can lead to hydrogen gas formation.

Hence, it could be dangerous to drain a hot water heater after more than two weeks of not using it without observing several precautions.

Also read: How long does it take to drain a water heater?


Should you drain a water heater when not in use? Yes, you should empty your appliance when not in use, especially if you leave home for extended periods and in the winter.

Draining and flushing a water heater is a significant maintenance activity, ensuring the unit lasts longer and guaranteeing optimal performance for the whole family.

Check out our article on how to drain a Rheem water heater for more detailed steps. It might be brand-specific, but the steps can also apply to other water heaters.

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