Why does water back up into my kitchen sink when the washing machine drains?

Author: Irwin Grady  |  Last update: Monday, September 22, 2025

Sometimes, water might back up in the kitchen sink while you're doing a load of laundry, or your bathtub will fill with water. Either case means that your main drain line is clogged. You need to call a professional to clear the drain for you.

Why is my washing machine drain backing up into my kitchen sink?

You may be able to solve the problem by using a drain snake to clean out the clog. Your washer drain may be easy to get into because the drain from the washer is often just poked into the drain hole, so you could pull it out and run the snake down there. It may be behind the washer or to the side of it.

How to stop a washing machine from draining into the sink?

  • Cable ties .
  • One cable tie around the drain pipe, one around the hose, and one linking the other two,
  • Put all three in place, tighten the two around the hose and pipe, and tighten the linking cable tie just enough to keep the hose in place but allow a little movement.

Why does my washing machine drainage gurgle into my kitchen sink?

One of the most common causes of a gurgling sink is a blockage in this main air vent. When there is a blockage, air can get trapped in the pipes. As the air tries to escape through the water in the pipes, it creates gas bubbles, and this is most often the source of the gurgling sound in your sink.

How do I fix the water backing up in my kitchen sink?

Pour one cup of fresh baking soda down the drain, followed by one cup of white vinegar. Place a rubber stopper or other sink hole cover over the drain opening. Wait 15 minutes to allow the vinegar and baking soda to unclog your drain, Then take out the drain cover and run hot tap water down the drain to clear the clog.

How to fix water coming up through your sink from the washing/laundry machine/dishwasher.

Why is water coming up my sink when the washing machine is on?

If your sink is backing up only when the washing machine is draining, for example, the likelihood is that the blockage is in the washing machine pipe. A clogged plumbing vent pipe may also be the culprit. Without proper air pressure, your sinks, shower and tub water might drain slowly.

How do I keep water from getting behind my kitchen sink?

Using an anti-splash guard is also a good move to prevent water splashing. The kitchen sink anti-splash guard is fixed to the sink, and you can choose to attach it to all sides of the sink; it can effectively block the water from splashing everywhere near your sink.

Why is my sink gurgling without blockage?

A gurgling sound in your sink is actually the sound of trapped air trying to escape from the drain. Your pipes should not have any air trapped inside, but they can become obstructed by food items like grease, seeds, bones, and rice that shouldn't go down your drain.

How should a washing machine drain be vented?

Run the Drainpipe Into an Existing Vent Stack

The easiest and most effective way to vent a washing machine is to run the drainpipe into your home's vent stack.

How do I stop my toilet from bubbling when my washing machine drains?

Washing machines must be installed correctly to prevent drainage issues that can cause toilet bubbling. Check Installation: Inspect whether your washing machine's drainage system is installed according to local plumbing codes. Ensure that there is an adequate air gap between the machine's drain hose and the standpipe.

How to unclog main drain line?

Your step-by-step guide: How to clear a main sewer line clog
  1. Step 1: Loosen the cap on the drain pipe. ...
  2. Step 2: Open the cap and let the buildup drain out. ...
  3. Step 3: Feed the auger cable into the drain pipe. ...
  4. Step 4: Run the auger until the clog is clear—and beyond. ...
  5. Step 5: Hose down the pipe and auger cable.

Why is water coming up my kitchen sink?

The most common cause of water backing up in your kitchen sink is a clog in one of the pipes or drains. This can be caused by debris such as food scraps, grease, and hair getting caught in the pipe and blocking the flow of water.

What will unclog a washing machine drain?

Clear things out by mixing equal parts of hot water and vinegar and pouring the mixture through the drain pipe. Wait half an hour, then reconnect the drain pipe, plug in your machine and run a wash cycle.

Why is kitchen sink backing up?

The most common causes of clogs include: Food debris: When food or grease builds up in your drain, it can completely block the pipes or stick to the walls, restricting water flow. Soap scum: It's common for soap scum and hard water minerals to accumulate in your pipes over time, causing a backup.

How do I know if my washing machine drain hose is clogged?

If there is standing water in the washer tub following the final spin cycle, or there is water leaking from the bottom of the washer cabinet, the washer's drain pump or drain hose could be clogged or broken and preventing the water from being emptied from the appliance into a laundry tub or standpipe.

Why is water coming back up my washing machine drain?

Washing machines overflow for a variety of reasons—the leading culprit, though, is a clog in the drain pipe. Lint and other debris come off of clothing during the wash cycle and are drained from the unit alongside the dirty water, potentially leading to clogs that can wreak havoc on your drain pipe.

Can a washing machine and sink share a drain?

Yes, with a Y-fitting, you can successfully connect a utility sink and washing machine to the same drain.

What happens if washing machine is not vented?

Failure to vent washers and dryers can lead to problems such as accidental fires, mold, condensation, and basement flooding. Both appliances generate tremendous heat and humidity and can wreak havoc in your home.

How high should a washing machine drain be?

In order for the drain hose on your Top Load Washer to function properly, the drain must be at least 30" up from the floor and less than 8 feet high. In order for the drain hose on your Front Load Washer to function properly, the drain must be at least 24" up from the floor and less than 8 feet high.

Why does my kitchen sink gurgle when the washing machine drains?

If the pipe that your washing machine and kitchen sink share for drainage is partially blocked, it can struggle to handle the volume of water from the washing machine. This can cause water to back up and pull air through the sink drain, creating a gurgling sound.

Where is the vent for a kitchen sink?

In most houses, the drain line for each sink extends horizontally back into a wall, where it fits into a sanitary tee. One outlet on the tee extends downward into a vertical drain line, and the other extends upward into a vent system that is open to the outside air.

Why does laundry water back up into my kitchen sink?

If your kitchen sink is backing up when washing laundry you may have a clogged drain or a venting issue, but it could be other issues. Start to identify the problem and contact your local plumbing company for help. To start with, know that your sink and washing machine drain lines tend to run congruent to each other.

How do I stop water from backing up in my sink?

Try the following:
  1. Remove as much water from the sink as possible.
  2. Pour one cup of baking soda down the drain.
  3. Follow up with one cup of white vinegar.
  4. Place the stopper over the drain hole to seal it.
  5. Allow the mixture to work for about 15 minutes.
  6. Remove the stopper and run hot water.

Are kitchen sink splash guards worth it?

Sink splash guards are useful accessories. They help minimize water splashing and keep sinks clean in kitchens and bathrooms. The guards have two roles: improving cleanliness and preventing water damage.

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