Water discharge hose with 180-degree U-shaped hose hook
Hose clip (optional)
U-shaped hose holder (optional)
Installing a washing machine is one plumbing task that doesn't require extensive experience or DIY know-how. Buying a new washing machine—or hooking up an old washer in a new home—is an exciting event, but setting it up can feel a bit daunting if you’ve never done it before. Our expert guide walks you through how to plumb a washing machine drain in eight simple steps.
Preparing to Plumb a Washing Machine Drain
Before you plumb your washing machine drain, it’s important to make a few plans and gather your equipment.
This guide assumes you have a drainpipe stubbed out of the wall where your washing machine will be installed. If you do not see either the washing machine box or the PVC drainpipe sticking out of the wall, your project may require cutting into the wall to alter the plumbing. In this case, skip to the end of the article to find out why it’s probably best to hire a plumber for the job.
Choose Your Laundry Room Location (If You’re Going to Change It)
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Perhaps you have a dedicated laundry room in your home, on the first or second level. Or maybe your laundry space will be in your basement or a restroom. Before you install your washing machine drain, you should choose the best spot for your washer and dryer.
If you move into a new home and aren’t happy with the designated laundry area, you can consider the cost to relocate washer and dryer hookups to suit your needs. That would be the perfect time to have your plumber install the standpipe needed for your washing machine drain.
However, if you’re installing the standpipe and P trap yourself, you’ve come to the right place for the necessary DIY installation info on plumbing a washer drain.
Gather Your Tools and Supplies
If you are buying a brand-new washing machine, it will likely come with the flexible discharge hose you need to connect your machine to the standpipe. When moving a washing machine to a new location in your home or a new house, you may already have what you need for the installation. The most important item you need is a water discharge hose with a U-shaped hook that keeps the hose from coming out of the standpipe. If you need a new one, they typically cost around $6.
Turn Off the Water and Unplug the Washing Machine
If you’ve already started setting up your washing machine, here are a couple of precautionary measures. Make sure to turn off the water supply to the washing machine as well as unplug the machine, just to prevent any mishaps with water or electricity during this part of the project.
Now you should be ready to get started on the fun part—installing your washing machine drain, aka the standpipe. You’re that much closer to that clean-clothes smell.
Locate the Drainpipe for Waste Water
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Assuming you don’t have a washing machine box installed in the wall already, you should find a short PVC drainpipe stubbed out of the wall in the laundry area. Again, if you don’t see anything that looks like this, you should call a plumber to install one or the other.
Cut the Standpipe to Length
To determine how long you’ll need to cut the standpipe, dry-fit the long, straight piece of PVC pipe to the P trap and elbow (put it together without using glue), and attach it to the waste pipe stubbed out of the wall. Adjust the standpipe so it is as close to the wall as possible.
Measure your standpipe and mark it so that when you cut on the mark the standpipe is at least 18 inches from the P trap weir (the lowest point where the water overflows into the drainpipe) but not higher than 42 inches above the trap weir, according to the International Association of Certified Home Inspectors.
You should end up cutting your standpipe somewhere between 20 to 24 inches long. That should be a safe range, depending on what length is best for your exact situation. However, be sure to check local codes for minimum and maximum standpipe heights. Also, make sure that your discharge hose reaches comfortably to what will be the top of your standpipe.
Assemble the Drainpipe
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Take the dry drain assembly apart and apply ABS cement (a 4-ounce container will suffice) as directed by the manufacturer and reassemble the pieces of your drain—standpipe, P trap, and elbow—and glue the elbow to the drainpipe stubbed out of the wall. Allow the cement to dry for the recommended amount of time.
Strap the Drainpipe
Secure the standpipe to the wall with four U-shaped strap clips. If you can, screw into the stud for a sturdier hold. Otherwise, use drywall anchors to make sure the screws stay securely fastened to the wall.
Remove the Transit Bolts
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New washing machines will have transit bolts on the back of the machine. These bolts need to be removed. Use a wrench to unscrew the bolt to remove it. If you do not have a new washing machine, you can skip this step.
The water supply hose will feature two ends: one at a 90-degree angle and the other at a straight angle. Attach the 90-degree angle end of the hose to the washing machine. You won't need any tools to do this as the piece twists on. The straight end of the supply hose attaches to the cold water tap, which you can tighten down without using tools.
Connect the Drain Hose
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Now it’s time to connect the drain hose from the washing machine to the standpipe. If you’re using the hose that came with the washing machine, follow the manufacturer’s directions. If you’re replacing the washing machine hose on your trusty old washer, follow the instructions with the new hose. You will essentially connect one end to the washing machine and hang the U-shaped hose hook on the standpipe so that the drainage hose empties into it.
Check for Leaks
Once everything is connected, turn the water back on and check for leaks at the cold water tap. Then run the washing machine on a short cycle to see how everything drains. You’ve got this, but have some towels and a bucket handy in case anything leaks.
Alternative Washing Machine Drain Option
If you don’t have a washing machine box installed or a drainpipe stubbed out of the wall, you can possibly connect it to a sink or an open pipe. Otherwise, you should contact a plumber.
Please note that hooking the drain hose to the side of a sink and draining into the sink itself may lead to flooding problems if the hose comes loose or if the sink drain becomes clogged or obstructed and overflows.
Connect to an Open Pipe
An open pipe will have a U-bend to the main pipe where you can drain the water from your washing machine. Drill the U-shape hose holder above the open pipe. Weave the drain hose through the hose holder.
DIY vs. Hiring a Pro
If you have some experience with minor household plumbing jobs, plumbing a washing machine is a simple task you can handle on your own. For homeowners who are uncomfortable working with plumbing, it may be a better idea to hire a professional plumber in your area to install your washing machine to give you some peace of mind.
Hiring a plumber costs between $180 and $500 for most projects, or $45 to $200 per hour, but it can be worth it—especially if the installation requires you to open walls and change any of the existing plumbing. Improper installation could lead to leaks inside the wall. Water leaks could create mold problems and carry harmful bacteria. Improperly vented gasses can build up and cause condensation, foul odors, and reduce the quality of the air in your home.
Yes, all plumbing fixtures in the home, including washing machines, need to be vented. This is typically done using a Wye joint. When drains aren't vented properly, they can give off hazardous fumes, such as sewer gasses. Proper ventilation prevents these harmful materials from getting into your home.
In some cases, a washer and a toilet can share a drain. However, they can only share a drain if you are connecting a washing machine to an existing toilet drain, not the other way around. Washing machine drain lines have a smaller diameter than toilet drains so if a toilet is connected to a washer drain, it could cause a sewage clog.
The drain hose for a top load washer should be no more than 5 inches down into the drainpipe. With front-load washers, the drain hose should be no more than 7 inches into the drainpipe. Some washing machine waste water drain hoses have a U-shaped hook that keeps the hose in the drainpipe and keeps it from going too far or not far enough into the drainpipe.
For a standard washing machine, the drain size is 2 inches, with a minimum requirement of 1 1/2 inches. A larger drain is typically required for modern washers if it's connected to your kitchen sink. Standpipes should be between 18 and 30 inches from the floor.