How To Vent A Washing Machine Drain Pipe With Easy Steps

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You recently purchased a washing machine for your laundry and discovered that you should vent the drain line to avoid flooding. You’d want to accomplish this, but you’re not sure how to vent a drain pipe. We completed the homework and are here to show you how to vent a washing machine drain line.

Assume you hear some sounds coming from your washing machine and the floor begins to flood. You panic and hastily turn off the water. The washing machine still has water in it, and the drainpipe appears to be stuck. You wonder if your washing machine pipe drain is ventilated or blocked.

How should a washing machine drain pipe be vented? A standpipe connecting to the P trap will be required. The drain will then be connected to the standpipe.

This is an excellent moment to contact a certified plumber. Let’s have a look at what a properly ventilated washing machine drain line entails.

washing machine

How To Vent A Washing Machine Drain Pipe

Make sure the washing machine is not plugged in, then proceed as follows:

  • Locate the water inlet valve and connect it to the red and blue cables at the rear of the washing machine.
  • Attach the filter to the drain hose tip with waterproof adhesive tape. This is commonly seen in washing machines.
  • Bend the drain hose tip into a U shape, then connect it to the drain hole next to the water inflow valve. After that, connect the drain hole to the main ventilation pipe.
  • To adjust the air pressure during draining, install an AAV, or air admittance valve, on the drainage pipe. Check that it is four inches above the P-Trap level.
  • Fill the washing machine halfway. To test it, turn it on and then drain it.

Venting its drain allows for more convenient washing with less effort. In this post, you’ll discover how to vent the washing machine drain pipe and learn about other connected topics.

Do’s and Don’t When Venting a Washing Machine Drain Pipe

When venting the washing machine drain pipe, keep these principles in mind. They can avoid problems that may develop during the process:


  • To avoid blockage, clean the washing machine’s filter screen. It is often positioned where the drainage hose is connected.
  • Position the washing machine at least three inches above the ground on a board. When the floor is moist, this will assist you prevent electric shocks.
  • Before doing your clothes, inspect the pipes for any damage.
  • Cover the valves with a frame or box to prevent minors from disconnecting the hoses.


  • If the vent is in poor condition, do not drain the water.
  • Don’t mix and match pipe diameters. Overly narrow pipes can cause hydraulic pressure, but too broad pipes can cause flooding. The drainage pip should be about 3-6 inches broad.
  • To avoid significant problems, do not do it without the advice of an expert.

Key Considerations To A Washing Machine Drain Pipe

Venting is required for all plumbing equipment, including washing machines. Improperly vented drains can be slow and loud, as well as release dangerous pollutants.

Properly vented drains allow the P-trap to accomplish its function, which is to keep sewage gases from entering your home. Significant amounts of water (such as that pouring from a washing machine) can cause a siphoning effect, sucking the water—and noxious gases—out of the trap and into the air if they are not properly vented.

When venting a washing machine drain, several important considerations must be considered:

  • the vent’s size
  • the placement of the drain vent
  • the distance between the washer and the vent
  • connecting other fixtures’ vents
  • appropriate horizontal vent slope
  • material for vent pipes (ABS, PVC, copper, steel, cast iron)
  • the vent pipe’s pressure class

Keep in mind that a separate vent from your washing machine to your roof is not required; in fact, most homeowners prefer a shared vent stack. When connecting several fixtures to one vent, they must be linked above the flood-level rim of the topmost fixture.

How Washing Machines Drain

Your washing machine, believe it or not, is a highly sophisticated mechanism. When your cycle finishes, a pump pumps the water out of the tub and into a washer drain pipe. This drain hose ascends towards a standpipe. Near the hot and cold water valves is the standpipe. Assuming everything is in functioning order, the water will flow upward and out into the standpipe, where it will be sent to the sewage line.

If something goes wrong during this procedure, the washing machine will not drain, and water may back up and seep into your bathroom floor.

Washing Machine Drain Overflow Prevention

Taking the following precautions can lessen the chance of a washing machine drain overflow:

Using a garment or lint bag can help avoid lint buildup within drainpipes.

Inspect and clean the lint trap or filter in the washer.

To ensure effective drainage, leave at least 1/2 inch between the drainpipe and the discharge hose.

Use correct detergents to avoid soap residue buildup.

Clean the hoses and drainpipes on a regular basis.

When Should I Consult a Professional?

If your washing machine is producing sounds, emitting a foul odor, or leaking water, you should call a professional plumber. Taking care of any problems as soon as they arise can frequently help you save money. The washing machine may need additional plumbing or drain line cleaning. This might be tough for the typical homeowner to repair, so contacting a professional plumber is the best option.


To avoid floods and other difficulties, it’s a good idea to vent the washing machine drain line. To enhance the efficacy of the vent, always aim for proper installation.

If you have other problems with washing machines, welcome to check the following guides!