Air in your water lines can cause sputtering faucets, cloudy water, and loud banging sounds. The good news is that it’s often a simple issue to fix, especially after plumbing work or a temporary shutoff. Using a method plumbers rely on to purge air from a system, you can usually restore steady water flow by refilling the pipes gradually and giving trapped air a way to escape.
With guidance from This Old House plumbing and heating expert Richard Trethewey, we explain how to confirm air in your pipes, clear it safely, and when to bring in a pro.
What Causes Air in Pipes?
Air can enter your plumbing system at several points, most commonly after plumbing work, temporary shutoffs, or municipal water line repairs. When pipes are drained and refilled, air pockets can become trapped. However, air doesn’t remain stationary once it’s in the system. As water flows, trapped air moves through the pipes and tends to collect at high points, where it can disrupt water flow and cause noise or sputtering.
In some cases, air may also enter through leaks or issues with well systems. These situations typically require a qualified plumber for a professional diagnosis.
Signs of Air in Your Water Lines
Air in your pipes often shows up as both noise and inconsistent water flow. You will typically notice the issue at one fixture before it spreads throughout the system. Look for any of the following signs:
- Hissing or popping sounds
- Sputtering water from faucets
- Irregular water flow
- Cloudy water that clears after a few seconds
Tools Needed for Fixing Air in Pipes
Before starting, gather a few basic tools to make the process easier:
- Adjustable wrench
- Bucket or large container
- Flathead screwdriver
- Towels or rags
Locating and Shutting Off the Main Water Valve
Before working on your plumbing, make sure the water supply is fully shut off. As plumbing and heating expert Richard Trethewey explains in This Old House Magazine, “The cardinal rule before starting any plumbing project: Turn off the water.”
The main shutoff valve controls water flow to your entire home. There are two common types:
- Ball valve: Uses a lever handle. Turn it 90 degrees so it’s perpendicular to the pipe.
- Gate valve: Uses a round handle. Turn it clockwise until it stops.
If the valve is difficult to turn, avoid forcing it. As Trethewey advises in the This Old House segment “How To Drain Pipes for the Winter,” forcing a stuck valve can cause damage under full water pressure.
Step-By-Step Guide To Remove Air From Pipes
Once the main water valve is shut off, you can clear trapped air by slowly refilling the system and giving it a path to escape.
Prepare the System
Before restoring water flow, open all drain stoppers and place towels around fixtures to catch any splashing. This helps prevent pressure buildup and allows air to move freely through the system.
Open Faucets and Fixtures
Open faucets throughout your home to create an escape route for trapped air. Start with the highest fixtures and work your way down, opening both hot and cold taps.
Be sure to include outdoor spigots, toilets, and any water-using appliances, such as dishwashers and washing machines. Missing even one fixture can trap air in part of the system. Create a path for trapped air to escape by opening faucets throughout your home. Start with the highest fixtures and work your way down, opening both hot and cold taps. Don’t forget outdoor spigots, toilets, and water-using appliances.
Restore Water Flow
Slowly turn the main water valve back on. As water refills the pipes, it will push trapped air out through the open fixtures. Let the water run until it flows smoothly without sputtering. This can take several minutes, depending on the size and layout of your plumbing system.
Once the flow is steady, turn off each fixture and check that everything is operating normally.
Dealing With Persistent Air Problems
If air continues after clearing the system, the issue may be more complex.
Well System Issues
In homes with well systems, recurring air often points to mechanical problems rather than trapped air alone. Common causes include:
- Cracked or loose pipe fittings
- Damaged foot valves
- Faulty well pumps
- Low water levels
- Waterlogged pressure tanks
These issues typically require a professional evaluation.
When To Call a Professional Plumber
While many cases can be resolved with basic steps, call a plumber if:
- The problem persists after multiple attempts
- You notice leaks or water damage
- Water pressure drops significantly
- You’re unsure how to proceed safely
Persistent air in the system usually indicates an underlying issue that needs expert attention.
Preventing Future Air in Pipes
Keeping your plumbing system in good condition reduces the chances of air entering the lines.. Preventing air buildup starts with maintaining a sealed, properly pressurized system.
- Check for leaks and repair them promptly
- Maintain consistent water pressure
- Service well systems regularly
- Flush your water heater annually to remove sediment
Common Mistakes To Avoid
Even small missteps can make it harder to remove air from your pipes or leave pockets of air behind. Keep these common mistakes in mind:
- Forgetting certain fixtures: Skipping outdoor spigots, appliances, or rarely used faucets can trap air in parts of the system.
- Turning the water on too quickly: Restoring pressure too fast can push air unevenly through the pipes and prolong the issue.
- Not opening both hot and cold taps: Air can be trapped in either side of the system, so both need to be cleared.
- Closing fixtures too soon: Shutting faucets before the flow runs clear can leave residual air in the lines.
Troubleshooting Other Pipe Noises
Other factors besides air can cause noisy plumbing. Understanding the unique signs of these problems can help you pinpoint the specific cause.
Water Hammer
Water hammer occurs when water flow suddenly stops, creating a pressure spike in your pipes. Trethewey explains that a surge can send shockwaves through the system, resulting in loud banging or rattling noises.
Loose or Vibrating Pipes
Pipes that aren’t properly secured can rattle or vibrate. Securing them with brackets or adding insulation can reduce noise and prevent damage.
Safety Considerations When Working With Plumbing
Safety should be your top priority when working with pipes. Here are some important safety tips to keep in mind:
- Always shut off the water before working on plumbing
- Be cautious around electrical components in wet areas
- Use protective gear such as gloves and safety glasses
- Take care when working with hot water lines.
Our Conclusion
Air in water pipes is a common issue that can often be resolved with a simple, systematic approach. By understanding how air enters the system and taking steps to remove it safely, you can restore normal water flow without professional help. If the problem persists, a licensed plumber can diagnose and fix the underlying cause.
