Sink Gurgling When Toilet Flushes

It's not uncommon to hear a gurgling sound coming from your sink when you flush the toilet. This is usually caused by air being forced out of the sink's drainpipe when the water from the toilet flushes down. In most cases, this is not a cause for concern, but it can be annoying. There are a few things you can do to try to stop the gurgling, such as:

Check the P-trap under the sink. The P-trap is a U-shaped pipe that is designed to trap water and prevent sewer gases from escaping into the home. If the P-trap is clogged, it can cause the sink to gurgle when the toilet flushes.
Clean the drainpipe. The drainpipe is the pipe that carries wastewater from the sink to the sewer. If the drainpipe is clogged, it can cause the sink to gurgle when the toilet flushes.
Vent the drainpipe. The drainpipe should be vented to allow air to escape. If the drainpipe is not vented, it can cause the sink to gurgle when the toilet flushes.

If you have tried all of these things and the sink is still gurgling, you may need to call a plumber to take a look at the problem.

Here are some additional tips that may help to stop the gurgling:

Don't put too much water in the sink. When you fill the sink with too much water, it can cause the water to overflow into the drainpipe and create a gurgle.
Don't flush the toilet while the sink is running. When you flush the toilet while the sink is running, it can create a vacuum in the drainpipe and cause the water in the sink to gurgle.
Install a venturi aerator on the sink faucet. A venturi aerator is a device that helps to mix air with the water coming out of the faucet. This can help to reduce the amount of gurgling.

If you have tried all of these things and the sink is still gurgling, you may need to call a plumber to take a look at the problem.