When Should I Drain and Flush My Water Heater?

Ben Kissam
Written by Ben Kissam
Updated June 9, 2021
Water heater inside house
Photo: JulNichols / E+ / Getty Images

In most cases, you will need to drain your water heater annually, but frequency depends heavily on water type and other factors

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How often should you drain and flush your water heater? No one likes waiting several minutes for hot water to come through when they shower. By draining and flushing your water heater regularly, you can decrease the chance of this happening. An annual drain and flush ensure sediment doesn’t build up in your tank, which can sacrifice water quality and lead to heating issues.

Do I Need to Flush My Hot Water Heater?

Yes. As part of your regular water heater maintenance schedule, flushing and draining your water heater regularly boosts the quality of water in your home. It could also save you money long-term, as you can prolong the life of your tank with maintenance. 

However, under certain circumstances, you may need to drain or flush your hot water heater more often than recommended. Not only does the type of water heater you own factor in—you also need to consider the type of water that comes to your home.

In terms of difficulty, flushing and draining your water heater isn’t too challenging. It’ll take somewhere around an hour to complete, and much of that time is simply letting the tank cool and drain itself. (A bigger tank will take longer, though.)

Why Should I Flush and Drain My Water Heater Regularly?

Your water heater fills with different types of sediment, such as limestone, chalk, and gypsum. These naturally-occurring minerals found in water wind up at the bottom of your tank over time.

Sediment buildup can result in temperature loss, longer heating times, and leaks. This is because sediment deposits sit on the burner plate at the bottom of your water heater and block the flow of heat.

There are many benefits of flushing your tank periodically and only one minor drawback to consider.

Pros

  • Lower energy bills

  • Preserve your hot water heater (the average unit lasts 12 years)

  • Reduces noise

  • Improved heating speeds

  • Removes smelly or old water from your tank

  • Allows you to inspect for signs that your water heater is failing

Cons

  • Flushing the unit could activate a leak that debris was blocking if it’s been several years since you’ve flushed it

How Often Should You Drain or Flush Your Hot Water Heater?

Not sure how often you should flush or drain your hot water heater? Depending on some factors, once a year is a good guideline to drain most water heaters. However, if you live in an area with hard water (high mineral content), it’s better to do it every six months or so. 

In general, though, an annual cleaning will help prolong the life of your water heater and ensure hot water makes its way throughout your home. That way, the dishes (and children) can stay clean and you never have to wait too long to take a hot shower!

Man draining water heater
Photo: Hispanolistic / E+ / Getty Images

Check Out Your Annual Water Supply Report

If you’re still unsure how often you should flush and drain your water heaters, check out your annual water supply report.

Water suppliers send out an annual report by July 1 that shares information about your water. You can learn about where it comes from, its mineral content, and more through this document. Remember, if you have hard water (higher mineral content), your water heater should probably be drained and flushed more than once a year.

The report is generally attached to water bills or available for download online.

What to Expect When You Flush a Water Heater

You’ll need to set aside at least 20 to 60 minutes to flush and drain your water heater, according to size. By the way: If you aren’t sure how big your tank is, a 50- to 60-gallon tank is typically big enough for two or three people.

You’ll also need to:

  • Know whether your water heater runs on gas or if it’s electric

  • Wait at least 20 to 30 minutes so the water in your tank can cool before you flush

  • Be ready for water to flow out at a rapid speed when you reopen the water supply—be careful!

You might get a little wet, so wear gloves and put on old clothes before you get started. (For the record, one of the benefits of a tankless water heater is that they’re less messy.)

How Much Does It Cost to Hire a Pro to Drain or Flush My Water Heater?

If you’re asking, “How often should I drain my water heater?” you might also be wondering how much it costs to hire a pro.

You’ll spend about $200 to have someone flush and drain your water heater. Although, you might be able to score a deal depending on the season. (Fall is a popular time to do it.)

If it’s been a while since your water heater has been flushed and drained, you should probably hire someone to do the job. A massive leak could force you to replace an older tank, which will cost much more than hiring a water specialist.

A licensed plumber is your best bet for getting the job done correctly and safely. At the same time, you might ask them to do other water heater maintenance or take a look at your tank yourself.

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