The first useful thing you need to know is the reason why this sound occurs. As water runs down a drain it enters the trap inside. This trap is present to stop odors travelling back up the pipes and into a room.
Once the water has passed through the trap it enters the main drain waste pipe and then makes its way into the main sewer. Some of these pipes are connected within properties and are positioned in steep slopes. This causes the water to flow quickly and at times can create a vacuum behind the flow. It’s this vacuum which sucks at the water passing in the trap resulting in the gurgling sound.
Fitting an air inlet valve is an effective way to stop this gurgling. To install one, cut the pipe exiting the trap as close to the trap as possible and fit a Tee piece. The air inlet can then be fixed to the top of a vertical length of pipe from the Tee piece. The pipes can be welded together to complete the job.
The air inlet valve works by allowing the vacuum to suck at air instead of any water which is in the trap. This means the water can run noiselessly from your shower, basin etc.
Author: Laura Davis