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How to Remove Air in Water Pipes

If air is coming out of your water pipes, don’t worry, you may be able to easily fix it yourself. Read on to learn how to tell if air is in your water pipes, and how to get rid of it.

Water shut off valve iStock

This Old House master plumber Richard Trethewey once said in an interview, “We plumbers sometimes have a tough job. We get called in to diagnose sounds, smells, noises. And things that happen sometimes, but not all the time.

And while you may need a plumber for certain noisy problems, if air is coming out of your water pipes, the fix may not require a house call from Richard.

What Does Air in Water Pipes Sound Like?

Air in water lines will likely sound like a hiss or pop(s) emanating from the pipes. The causes can range from the simple to the complex, with the source of the air varying depending on the situation. Obviously, if you’re having your bathroom remodeled, this is probably it.

How Does Air Get Into Pipes?

The water has been shut off. New plumbing has been added, and air has been introduced into the system when it was depressurized and drained. Similarly, if your municipality is working on your neighborhood’s water lines, it’s the same story. Air’s been introduced into the system.

If you have a well, a similar condition can occur, though wells introduce complexities that transcend the scope of this article, with issues ranging from pump interruptions to drought, and it’s best to consult a professional for instances like this.

Steps for Getting Rid of Air in Water Pipes

For most occurrences where air in water pipes seems to be the problem, the fix is pretty easy—and requires you, the homeowner, to do a few things, the first of which is to shut off the main water valve in your house.

Step 1: The Main

If you own a home, you should know where the “main” is—and that it operates!

The main—or “shut-off”—is the valve located where the water enters your home. In older homes, the main is probably an old-school, star-shaped, garden-hose-style gate valve. Lefty-loosey opens it. Righty-tighty closes it.

If you have air in the plumbing, shut this valve off. If it doesn’t shut off easily or completely or is calcified from hard water, do not force it to move. Call a plumber (and switch it to a lever-type ball valve).

Step 2: Allow Air Out 1/2-Turn at a Time

If there is air in the plumbing, the idea is to systematically give it a path out.

Once the main is shut off, open all the faucets about ½ turn, both hot and cold. Run the dishwasher.

Run the laundry. Flush all the toilets. Open the hose bibs outside. Drain the pot filler and fridge water line.

Step 3: Re-Supply Water

With everything open, re-supply the system from the main. Turn the water back on and let it run for 10-15-minutes and make sure everything is working as it should. Let the toilets re-fill and re-flush them. Everything should be back to normal, water-flowing, civilized perfection.

If the noise you heard was a water hammer (or pipe hammer), the problem is that there is a poorly stabilized pipe or overly high-water pressure in the system. If you’re unable to determine the cause of the sound, call your plumber for a diagnosis.

If you are able to determine that the water hammer is from unsecured piping, installation of a water hammer arrestor may be the solution. And if you’ve concluded that the sound comes from elevated water pressure, give your plumber a call.

If you have a well and the problem of air in the plumbing system persists after taking the above steps, the problem may be more complex and isolated to your system. In this case, contact your well specialist.