5 Washing Machine Drainage Options To Choose

Whether you want to move the washing machine from one space to another or renovate your laundry room, you might wonder what the best drain option is. Should you hook the hose to a sink drain or use a dedicated drainage pipe? Are there alternatives?

The most common drain option for washing machines is a dedicated drain standpipe. Installing a standpipe and hooking the washer to it is an easy DIY project. Popular alternatives include sink connections and underground pipe links. You can also connect the drainage hose to a floor drain or run the washing machine drain outside.   

Common Washing Machine Drainage Options 

When it comes to clothes washers and draining, there are plenty of drainage ideas to inspire you. However, you must keep in mind that all the drains in a house must comply with the plumbing code. 

1. Dedicated Drain Outlet 

A dedicated drain outlet is the most popular option. Installing a washer drain outlet isn’t complicated, but you might have to install an additional plumbing vent if you can’t connect the standpipe to a vent stack. 

As mentioned above, you must install a pipe with a diameter of at least two inches. However, consult your local plumbing code before buying the pipe. Some regions or cities may have different requirements. In addition to the drainpipe, you must also install a P-trap

Draw a waste pipe diagram to decide the best pipe route from the wall drain to the washer. As a general guide, you must install the trap at least six inches but no more than 18 inches from the floor. The standpipe can extend at least 18 inches and no more than 30 inches above the trap.

Washers generally come with drain installation kits for easy hooking to the drainpipe. If yours doesn’t, you must also invest in a drain hose connector to connect the hose to the standpipe.

2. Utility Sink Drainage 

Installing a dedicated drain outlet can save you all the trouble in case of an inspection. However, you don’t have to add new plumbing to your laundry room if you don’t want to. One of the most common alternatives is draining the washer into a utility sink drainage. 

Connecting a washer to a utility sink drain is similar to connecting a dishwasher to the kitchen sink pipe. Just check your local building codes beforehand to figure out what size drain pipe you need.

You may be able to install a 2-inch PVC pipe, but some local codes may require a larger pipe diameter for a sink drain that also services a clothes washer.

If your utility sink has a smaller pipe but is deep enough to hold as much water as your washer may use during a cycle, you can also drain the washer directly into the laundry tray. No drain hose installation is needed in this case other than securing the hose to the sink edge to prevent it from falling down as the washer empties out.

3. Underground Pipe Link

An underground pipe link is one of the best washing machine drainage options if you’re installing a washer in a permanent location. 

This configuration requires a P-trap and standpipe, but instead of connecting the P-trap to a wall drain, you have to install a new drain pipe that feeds the wastewater directly into your wastewater storage through the floor (and underground, once it exits the house). 

Installing an underground pipe link is more complicated than installing a standpipe. Not only will you have to dig trenches into your floors and the ground, but you also have to maintain a slope towards the wastewater storage. It is best to hire a plumber for this job.

Washing Machine Drain Alternatives

None of the common washer drainage options above suits you? You needn’t lose hope. There are a few alternative ways you can use.

1. Laundry Sump Pump

Draining a washer into a sump pump is generally frowned upon. However, you can still drain directly into the laundry sump pump if the water is then pumped directly into the sanitary system. 

This option is ideal for basement laundry rooms, the sump pump pumping the greywater from the washer and utility sink to the ground floor level and then into the wastewater storage.

2. Outside Your Home

If you’re into green living and eco-friendly practices, know that you can also drain the washer outside of your home into a water reuse system. You can then use this water for irrigation purposes, and installing a drainage pipe that leads to your backyard is easy. 

How To Run Washing Machine Drain Outside?

  1. Plan the drainage system. Depending on where your washing machine is located, you may need a sump pump, a barrel to collect the wastewater, and a sufficient length of pipe to go from the washer to the collection container. You can also connect the drain to an irrigation channel.
  2. Install the drain. Connect the drainpipe to the washer hose first, then run it to the collection container or the irrigation channel, following your diagram. You may have to cut holes in a wall to run the tubing from indoors to the outside of the house.
  3. Check the connections. Before running your washer, make sure all connections are watertight and functional. 

Pro tip: While you can reuse the washing machine wastewater regardless of the type of laundry detergent you use, a biodegradable, eco-friendly detergent is less likely to damage your plants or lawn.

What Type Of Drain Does A Washing Machine Need?

According to the Universal Plumbing Code, a washing machine needs a dedicated 2-inch drain pipe with a P-trap. However, regional and local codes may have different requirements. Most local codes also allow alternative drainage systems, including the ones mentioned above.

Washing Machine Drain Hose Backflow Prevention 

No matter what drainage system you want to install, it is crucial to consult a licensed plumber to prevent backflow. 

Washing machine drain hose backflow can happen if the drainpipe is incorrectly installed. A kinked hose and clogs are other potential causes. If the wastewater flows back into the washer, it can overload it and lead to floods.  


Is it illegal to drain a washing machine outside?

Draining the clothes washer outside is legal in most states. According to the code, you can even reuse the water for irrigation. However, reusing laundry water can be illegal in your area. Always check your local building and greywater collection codes before draining the washing machine outside.

Does a washing machine need a dedicated drain?

A washing machine doesn’t need a dedicated drain, as long as you can connect it to a sink or laundry tray drain that is large enough to serve both the fixture and the appliance. 

To End

Whether you want to install a permanent plumbing system for your washer or drain the appliance temporarily into a fixture or container, there are many drainage options to choose from. We hope this guide can help you decide which one works best for you.

Recent Posts