Why is my sink filling up with water when my washing machine is on?

Author: Gerda Emmerich  |  Last update: Monday, July 7, 2025

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 my washing machine from backing up into the sink?

Either case means that your main drain line is clogged. You need to call a professional to clear the drain for you. Luckily, you can avoid major clogs by not putting food and grease down your kitchen drain. There are also enzymes available that can help keep pipes clear and remove minor blockages.

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

If you are seeing water burble up from a utility sink next to your washing machine while you are washing clothes, then it's very likely that you have a lint/hair clog in the drain line just down from the washing machine that needs to be snaked out.

Why does my sink overflow when the washing machine runs?

Excessive water usage: Your washing machine might be using too much water, either due to incorrect load size settings, malfunctioning water level sensors, or a faulty inlet valve. This excessive water usage can overwhelm the drain system and cause the sink to fill up (2).

Why is water coming out of drain pipe for washing machine?

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.

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

How do I know if my washer drain is clogged?

Recognizing early signs of a clog can prevent more serious issues, such as machine damage or flooding. Keep an eye out for these indicators: Slow Drainage: Water draining slower than usual suggests a partial blockage. Standing Water: Water remaining in the drum after a wash cycle indicates a significant obstruction.

How to stop sink water from going into a washing machine?

Secure it with the hose support crook delivered to you in the accessory pack that you found in the drum on delivery of the product. Fitting it up at this way allows the sink overflow will act as what plumbers call an 'air block' which will stop dirty sink water backfilling into your washing machine.

Why does my plumbing back up when I run a washing machine?

If water is backing up after a couple of loads, it probably means the backup is past the toilet and may be a clog in the main line. Your lines need cleared from a main line cleanout, which is a professional job for plumbing companies.

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.

How do you fix a washing machine drain pipe overflow?

The easiest way to fix this is to seal up the washing machine waste hose against the open PVC pipe. Some gaffer tape should do the trick. Otherwise you could fit a holding tank above the drain which is allowed to fill and provides time enough for it to drain out without overflowing.

Can a washer and sink share a drain?

Sharing a drain between a washing machine and a sink can be a practical solution, offering space and cost-saving benefits.

Why is my sink bringing water up?

So, when you notice water backing up through the plug hole instead of smoothly draining away, it's a cause for concern. This unexpected issue is a clear sign of a problem in your drainage system, most likely a stubborn blockage.

Why does sink fill up when washing machine is on?

WATER IS NOT DRAINING OUT OF THE WASHER

Things like jammed pump impellers, broken belts, electrical pieces, or other broken parts can directly cause this issue. Keep in mind that a plumber can assist you if the issue resides within your pipes or your home.

How to clean a washing machine drain hose without removing?

Use a funnel to pour about a quarter of a cup of baking soda into the pipe. Next, empty a baster full of vinegar into the drain hose. Top tip: If the blockage is not completely gone, you can repeat the above process. Once you have cleared any debris from the hose, pour hot water in to flush everything out.

Where is the main drain in a house?

Main drains are located in the walls and floors of your home, while sewer line drains are located outside underground. Each drain pipe in your home is connected to a different household fixture on one end, including toilets, sinks and bathtubs, and the other end is connected to the main sewer line.

Why does my sink fill with water when I run the dishwasher?

A drain clog is one of the primary culprits for why your sink fills up when you run your dishwasher. Over time, food particles, debris, and grease can gather in the sink and dishwasher drains, restricting the water flow. As your dishwasher pumps out water, the clog may cause a backup, leading to water filling the sink.

How to unclog a laundry drain pipe?

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.

Can washer cause plumbing issues?

If you have a clog in the washing machine drain, it could impact the plumbing in the rest of your home. When your washing machine doesn't drain, check if the other drains in your home also have clogs. If so, you may have an issue with all your plumbing.

Why does water drain back into my washing machine?

Your drain or hose is clogged. Your load was too large for a good spin cycle. Your washing machine's sensors are damaged or old.

Why is water coming back into my washing machine?

Why does my washer keep filling with water? If your washing machine water won't shut off, there are a few possible causes: A damaged water inlet valve. A broken water level switch.

How to stop water from coming back up a drain?

Test balls, twist plugs or pressure plugs can be installed to seal floor drains but will not let water flow in either direction. If plugs are not available, a flexible rubber ball that is just larger than the pipe diameter can be used in an emergency but will need to be braced in place.

How much does a plumber charge to unclog a washer drain?

Kitchen sink or laundry drain cleanout – $150 to $275 average cost. Main sewer line augering – $200 to $500 per cleaning.

Will Drano unclog a washing machine?

Drano® Snake Plus Tool + Gel System was designed to unclog a kitchen sink, bathroom sink, shower, bathtub and even a laundry drain.

How do I clear my washing machine blockage?

There are three recommended methods of unblocking a washing machine drain yourself. These are to use baking soda and vinegar, a chemical drain cleaner, or do it manually. You can also potentially fix the issue by straightening out the washing machine drain hose if it has become twisted.

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