How To Vent A Washing Machine Drain Pipe (Step By Step)

A vent’s function is to ensure that your washer’s drain pipe does not overflow. This alone is reason enough why you should know how to vent a washing machine drain pipe.

To vent a washing machine drain pipe, you must clear every possible blockage. 

Doing so is an easy way to prevent the machine from leaking, which may cause your basement or laundry room to flood. Improperly vented drains can be sluggish and noisy and can emit hazardous fumes. 

In this article, I will explain how to vent a washing machine drain pipe and what things you should keep in mind while venting a machine.

Vent A Washing Machine Drain Pipe

How To Vent A Washing Machine Drain Pipe (Step By Step)

If your washing machine does not have a vent, it will cause the drainpipe to overflow because of excessive pressure. Aside from this, it can also affect the performance of the drain trap. 

Following are the steps to vent a washing machine drain pipe.

1. Locate The Drain Pipe

Locating a drain pipe and then choosing a vent route are the most critical steps in this process.

It is important to locate the drain pipe, which will usually be attached to the back of your washer.

The vent route is chosen based on your washing machine’s location to ensure it is within the shortest distance possible.

If your washer is set up in an underground basement, you must run the vent duct up. It will be passing through the exterior wall and rim joint. 

The vent should be 12 inches above the ground outside, and you will need 24 feet of 4-inch wide duct to run the vent from the basement.

If your washer is close to an exterior wall, it is easier than running it from an underground location. You can just run it straight out. 

The length of the duct required would also be shorter. But make sure that the vent is elevated by at least 12 inches from the ground outside.

If your washing machine is inside your house’s interior room, the vent will run through the roof and the attic. But in my opinion, installing it through the roof is not advisable unless it’s a last resort. 

This is because birds and squirrels nest on the vent caps over time. Nesting on these caps can cause an obstruction; you might need to check it frequently to avoid overflowing the drain pipe.

2. Install The Vent Cap

Find an ideal location to drill the vent hole and ensure it fits the siding. Once you have drilled screw holes into the designated area, screw the vent cap onto it.

Follow the steps below to install a vent cap properly.

  1. Drill a vent hole at an ideal location and ensure it fits the siding.
  2. Rest the top of the vent cap on the lap siding’s high point, and then remove the cap from the duct so that you can take its measurements.
  3. The hole should measure about 4 ½ inches, and make sure to remove the debris. 
  4. Once done, look for deep gaps, push foam backer rods through any you find, and seal the area with acrylic caulk. 
  5. Drill the slightly oversized holes into the vinyl siding to enable movement. 
  6. Insert a vinyl mounting block against the siding. Install the siding afterward to fit around the block.

3. Connect The Ducts

Avoid using screws or duct tape to connect the ducts. Instead, use metal foil tape to keep the link in place.

Following are the steps to connect the ducts properly without any obstruction.

  1. After installing a Vinyl Surface Block for vinyl siding, connect the elbow fittings.
  2. One fitting should be placed on the drain pipe output and another on the outer vent. Be careful with them since they give strength to the structure.
  3. Then, start cutting the vents according to the measurements you’ve taken for the structure. Only one duct section should lead from the washer to the outside.
  4. Once you have aligned the seam edges, connect one end of the first metal duct to the elbow fitting, joining it to the crimped end of the elbow.
  5. Insert the rest of the ducts into the crimped ends of the elbow fittings. Use metal foil tape to hold the ends together and screw it to the wall.
  6. The last step is to plug the washer in and turn it on to try it out. Check outside to make sure that the vent flap is opening correctly.

Why Should You Vent a Washing Machine Drain Pipe?

Following is a list of reasons why you should vent a washing machine drain pipe:

  1. It prevents vacuum formation in the drain, affecting wastewater removal.
  2. It prevents overflow, as lack of venting can cause a washing machine to drain slowly.
  3. Sewer gas contains harmful microorganisms, which can be hazardous when inhaled, and some gases tend to be flammable. So having a drain tap prevents a fire hazard.
  4. It keeps negative pressures from pulling the water out and rendering the drain trap useless.

Does A Washing Machine Drain Hose Need To Be Elevated?

Yes, the drain hose needs to be elevated. It’s always best to do so at a higher level than the washing machine.

When installing a washing machine, it’s important to understand the proper height and placement of the drain hose. 

This will ensure there’s less risk of potential overflow while helping prevent flooding in your laundry room. It will also prevent possible siphoning.

This gives you the best possible drainage and ensures that your washer and dryer get the necessary ventilation.

Final Remarks

It’s incredibly frustrating to learn that you need to vent the drain pipe of your brand-new washing machine. But doing it at home ensures you can overlook how everything is done and saves you about $500 to $800.

The main steps to vent a drain pipe are as follows.

  1. Locate the drain pipe
  2. Install the vent cap
  3. Connect the ducts