Solving A Washer Backing Up Into A Sink: 9 Easy Steps

Is your washer water backing into your sink and creating a messy, soapy situation? 

I feel your pain. This issue can be a real headache for retired homeowners like you, but don’t worry. You’re in the right place. 

In this article, I’ll walk you through nine simple steps to fix the problem, ensuring that your washer and sink coexist peacefully.

We’ll cover essential fixes like checking the drain hose for clogs, ensuring your sink’s plumbing is in good shape, and even some preventive measures to prevent the issue from happening again. 

Grab your tools, and let’s stop that washer water backing up in your sink.

What You Will Need:

  1. A bucket
  2. A pair of gloves
  3. A drain snake or plumber’s auger
  4. A pipe wrench
  5. A plunger
  6. A flashlight

Solving A Washer Backing Up Into A Sink: 10 Easy Steps

#1: Turn off the Washer

Before you begin, turn off your washing machine and unplug it from the electrical outlet. It will ensure your safety while working on the issue.

someone turning off the washer
Turn off the washer – Safety first

#2: Inspect the Drain Hose

The drain hose is a flexible, usually ribbed, tube that carries the water from your washing machine to the drain. It is typically located at the washer’s rear and connected to a small port on the back. To access the drain hose, pull the washing machine away from the wall so you have space to work:

Hand Holding Clogged Drain Hose
Here’s how the drain hose looks like, locate it and check for blockages
  • Locate the drain hose at the back of the washer; it usually has a curve and connects to a port on the machine.
  • Check the hose for any visible blockages, kinks, or damage.
  • If necessary, disconnect the hose by loosening the clamp or connector that holds it in place. If you lean the washer on two feet, lean it against the wall front, so the front of the washer is leaning against wall, the connection for drain pump is at the back. It will force water to the front so less will spill out the machine.
  • Once disconnected, run water through the hose to see if it flows freely. If the drain hose is clogged, it won’t have enough force to push enough water fast enough to make the sink fill up with water
  • Clear any blockages or straighten out kinks before reconnecting the hose to the washer.

Pro Tip:

Spray glass cleaner in front of and around washer, so as soon as feet touch it , it will easily glide across the floor

#3: Check the Standpipe

The standpipe is the vertical pipe where the washing machine’s drain hose connects to your home’s plumbing. It is usually located near the washing machine and looks like a tall, vertical pipe with an opening at the top for the drain hose. To check the standpipe for clogs:

  • Locate the standpipe; it should be close to your washing machine and may be in a laundry room, utility room, or garage.
  • Remove the drain hose from the standpipe (if it’s connected) and set it aside.
  • Use a flashlight to look down the pipe for any visible obstructions.
  • If you find any blockages, use a drain snake or plumber’s auger to clear them out.

However, if there is something reducing water drain from the washer, it won’t fill up the sink as there is a blockage in the washer or line or drain line.

#4: Inspect the Sink Drain

The sink drain is the opening at the bottom of your sink that allows water to flow into the drain pipe. It is covered by a metal or plastic strainer to catch debris. To inspect the sink drain for clogs:

  • Clear any dishes or objects from the sink to access the drain.
  • Remove the sink’s drain cover or strainer by gently lifting it out.
  • Use a flashlight to inspect the drain pipe for any visible blockages.
  • If you find any obstructions, use a drain snake or plumber’s auger to clear them.

#5: Examine the P-trap

The P-trap is a curved pipe under your sink that prevents sewer gases from entering your home. It’s shaped like a “U” or “P” and connects the sink drain to the main drainpipe. To inspect the P-trap for clogs:

  • Place a bucket or container under the P-trap to catch any water that may spill out.
  • Loosen the two slip nuts on either side of the P-trap using a wrench or a pair of pliers.
  • Carefully remove the P-trap and pour any water inside into the bucket.
  • Check the P-trap for debris or clogs, and clean it if necessary.
  • Reassemble the P-trap and tighten the slip nuts securely.

#6: Clean the Air Gap (if applicable)

Some washing machines have an air gap, a small device installed between the drain hose and the standpipe. It prevents dirty water from flowing back into the washer. To clean the air gap:

  • Locate the air gap; it’s usually a small, cylindrical device near the sink or washing machine.
  • Remove the air gap cover, which may be secured with a screw or snapped in place.
  • Clean any debris from the air gap and its openings.
  • Reattach the cover, ensuring it’s secure.

#7: Verify Proper Venting

Proper venting is crucial for your plumbing system to function efficiently. A blocked vent can cause water to back up into your sink. To check your venting system:

  • Locate the vent pipe on the roof or near the washer’s standpipe.
  • Inspect the vent pipe opening for visible obstructions, such as leaves or debris.
  • If necessary, use a plumber’s snake or a garden hose to clear any blockages in the vent pipe.

#8: Test the Washer

After addressing any issues, run a small load of laundry to see if the problem persists. If the washer still backs up into the sink:

  • Turn off the washer and consult a professional plumber or appliance technician.

#9: Prevent Future Issues

To avoid washer water backing up in the sink in the future:

  • Regularly clean your sink drain, P-trap, and air gap (if applicable).
  • Check the drain hose for kinks or damage.
  • Ensure the drain hose is at the correct height.
professional inspecting washer
Always call a professional technician for inspection to prevent further issues


Dealing with a washer backing up into the sink can be frustrating, but with these nine easy steps, you can tackle the issue head-on and restore your laundry routine to normal. 

By understanding the various components of your washer and sink plumbing system, such as the drain hose, P-trap, air gap, and venting, you’ll be better equipped to diagnose and address the problem. 

Remember that regular maintenance and inspections can go a long way in preventing future issues. 

If you need clarification on any steps or additional guidance, feel free to seek professional assistance from a plumber or appliance technician. With patience and persistence, you’ll be able to conquer your washer water backing up in the sink problem and enjoy hassle-free laundry days once again.

Hi there! I’m Craig, and I’m the founder of Appliance Analysts. When it comes to appliances and anything electrical, I’ve always loved opening things up, figuring out how they work, and fixing them. This website is where I share free advice from myself and our experts to help our readers solve their appliance/HVAC problems and save money. Read more