How to Repair Gurgling Drains

Gurgling drains may be a common problem, but they are also a sure way to tell there’s something not quite right with the air in the pipes. Often, air is supplied through vents, so the gurgling could indicate the vents are blocked or installed incorrectly.

If you find the gurgling occurs when you use your sink, you’ll need to focus on the sink vents. However, if it happens when you flush the toilet or drain the bath, you’ll need to examine the entire vent system, which could be a bigger job.

What Makes the Gurgle?

When we drain a sink or flush our toilets, a head of water enters the waste pipe. The water filling the pipe means air is pushed in front of it and it then creates a vacuum. The vacuum creates a considerable internal force on the pipes, and a vent means more air can come and fill it. Without the vent, the air will enter through any available opening, i.e. the sink, shower or bath. The infamous gurgling sound is where air rushes past the water standing in the sink.

Repairing the Sink Vent

When gurgling occurs when the sink is being drained, it’s likely to mean there’s an issue with the sinks vent. This could mean that the vent hasn’t been installed correctly, or it could be blocked. For 1 ½ inch drain pipes, the vent should be installed within 3 ½ feet of the bottom of the trap. If the vent if further away than that, it’s likely a vacuum has developed and is the reason behind the gurgling. If your sink doesn’t have a vent, it could be the air admittance valve that’s causing the gurgling. Check the operation of this valve to ensure it’s working correctly, as it may have gotten stuck.

Repairing the Main Vent

If you find you’re hearing the drains gurgle when you flush the toilet or drain the bathtub, this probably means there’s a problem with the main drain vent. Gurgling here is a sure sign that you need to clean the vents before the vacuum gets too much and drains the sink trap. If this happens, your home could end up smelling of the sewers. To clear the main vent, you’ll need to go up to the roof and spray water into the vent opening, often located above the bathroom, or by using a sewer auger. The auger you use will need to be long enough to reach the sewer, as the blockage could be anywhere between the sewer and the vent opening itself.

Drain blockages can happen often, and you may find yourself having to deal with them frequently. If you notice the gurgling sound and do something to stop it as soon as possible, it’s likely you’re able to save yourself from drain cleaning and unblocking as regularly, as the free air passing through the pipes restores the natural flow of water.

If you’re still unsure and would prefer to leave the drain blockages to a professional, here at Drain Checker we’re happy to help. Get in touch with a member of the team today by visiting our contact page or by giving us a call on 0800 849 8099.