6 Signs You Need to Bleed Your Water Heater

By Melanie Dawn

July 06, 2025

There’s nothing quite like a long, hot shower at the end of the day. But have you ever turned on the hot water, expecting a steady stream, and instead been met with sputtering and spitting? These sounds and inconsistent water flow happen when air is trapped inside your hot water lines. Usually, it’s not a sign of a serious problem, especially if you’ve recently had plumbing work or an interruption of water service.

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However, if the problem continues, you should bleed your water heater.

What Does It Mean to Bleed Your Water Heater?

To bleed your water heater, you'll need to remove trapped air from your water pipes. Bleeding your water heater is often confused with flushing a water heater, which involves draining the tank to remove sediment buildup.

When air gets trapped inside your water lines, it creates pockets of air that can disrupt the flow of water to your faucets. Bleeding the line is a simple process of forcing this air out until water starts flowing freely again.

What Are Some Signs That You Need to Bleed Your Water Heater?

When you have air in your plumbing system, it'll be obvious. Here are a few signs to look for:

Sputtering and Spitting Faucets

The most common sign you need to bleed your water heater is gurgling, banging or knocking noises when you turn the water on. This happens when air bubbles are pushed around in the water flow. Typically, it won’t go away on its own. Leaving it puts a strain on your plumbing system.

Low Water Pressure

Air in your water pipes creates uneven water pressure throughout your home. If one faucet runs strong while another barely drips, it’s a good indication of air somewhere in the system. Bleeding your water heater can restore normal water flow.

Inconsistent Water Temperature

If you turn on the hot water and it goes from hot to cold without warning, it could mean water isn’t circulating as it should. When air traps hot water within the pipes, it can cause inconsistent temperatures.

Cool Radiators or Baseboard Heaters

Homes with hot water heating systems may not operate properly with air in the lines. Check your radiator or baseboard heater. If it feels cool to the touch, it may be time to bleed air from your system.

Air Bubbles in Expansion Tanks or Pipes

In some systems, you can see air bubbles moving through the pipes.

You’ve Recently Drained Your Water Heater

If you’ve recently had your hot water tank drained and refilled, you may experience air in the lines. This can happen after flushing the tank or if your water service has been interrupted. To ensure uninterrupted water flow, bleed the lines.

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Why It’s Important to Bleed the Air Out

It’s never good to ignore trapped air inside your plumbing system. Doing so can lead to damaged plumbing parts and faucet components. Bleeding the air out of your water tank restores performance and eliminates annoying noises.

How to Bleed Your Water Heater

Bleeding the air from your hot water system is an easy DIY task that requires very little plumbing know-how and no special tools.

  • Turn off the main breaker. For electric heaters, turn off the main breaker to your system. If you have a gas water heater, turn it to the pilot setting to prevent the heating elements from running dry if the water level inside your tank drops.

  • Locate the highest faucet in your home. Determine which faucet in your home is the highest. Continue opening faucets until they're all on to help move air through the system. Let the water run for several minutes until it stops sputtering and air escapes.

  • Turn off the faucets. Close all the faucets in the reverse order you turned them on.

  • Restore power. Restore power to your water heater or turn the gas back on.

  • Calling a plumber. If you bleed your water heater and still have uneven water pressure or air in the system, you may need to contact a plumber. This could be a sign of a more serious plumbing issue.

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