If your sink is making a gurgling noise, it's most likely being caused by air in your drain system. There are several possible causes, including a vent issue, a drain pipe blockage or a problem with your septic system. There's also the possibility of a faucet making a gurgling sound, which is also caused by air. The key to finding a solution to this problem is to first find the cause of it.
A Faucet Making a Gurgling Sound
When a faucet or sink makes a gurgling noise, it's due to air. There are a few reasons why you might have a gurgling faucet. If your house gets its water from the city water supply, it's possible that there has been recent work done on the city water pipes in your area. If the pipes have been worked on, air can get into the lines feeding the area homes. This usually clears up in a few days, but during that time you might end up with air and even sand or sediment coming from your faucets.
If your home gets its water from a well pump, a gurgling faucet can be a sign of a leak somewhere in the line from the pump to the house. If you also notice sediment in the water, it's likely that the well water level is low. Air and gurgling from the faucet can also be caused by a pressure tank with a ruptured bladder.
An Issue With a Drain
For homes with a septic tank, a gurgling noise is often an indication that the septic tank is full and needs to be pumped out. The first sign of a full septic tank is usually a gurgling sound when flushing the toilet. You will also hear gurgling sounds from your sinks, and your sink will either drain slowly or not at all.
If your house drain connects to the city or town sewer, a gurgling noise from the drain could be caused by a plugged drain pipe. This can also be the case if you're on a septic system. Sink drains tend to clog because of a buildup of food, hair or grease. A plunger can often be used to unclog a sink drain, and if that doesn't work you can try a drain auger. If neither of these work, you can pour a chemical cleaner down the drain, although this should only be used as a last resort.
An Issue With a Blocked Vent
Another possible reason for a gurgling sound in a sink is a blocked vent. Vents are an important part of your home's drainage system. If a drain system isn't vented, it will form a vacuum and won't drain. If the vent is blocked, air can't escape through the vent and will go out the nearest opening, which is often the sink. The gas escaping back up the drain line causes the gurgling noise and can also result in foul odors coming from your drains.
Among the causes of blockages in vent pipes, which are vented out through the roof of the house, are leaves and animal nests. A blocked vent is usually cleared from the roof by running a drain auger down the vent pipe. Because this can be dangerous, you may need to hire a professional to clear your vent pipe.
Gary Sprague is a retired master plumber who now works as a writer. He lives with his family in Maine.