How to plumb a washing machine drain pipe, valve, and more.

Can I plumb in a washing machine myself?

For homes already equipped with an old washer, installing a new one is a simple task, even for inexperienced DIY-ers. However, installing washing machine plumbing is a much more involved process. 

Only those with considerable plumbing knowledge should consider taking on this project without consulting a professional. Unless you have extensive plumbing experience, it’s probably best to hire a plumber. Even a small plumbing mistake can have disastrous consequences. 

What you’ll need.

The exact parts and tools you’ll need will vary depending on your laundry room layout and the existing plumbing in your home. In general, you should have the following on hand:

• Pliers. Any pair of pliers should be sufficient, but a pair of slip-joint pliers can be especially handy for tightening fixtures of varying sizes.
• Wrench. Pliers may strip or damage brass fixtures, so you should also have an adjustable wrench.
• Pipes and fittings. If you plan to tap into your water supply and drain lines, you’ll need tee fittings. Most washing machine plumbing systems use PVC pipes, but older homes may have metal pipes.
• Fixtures. Depending on the plumbing you already have installed, you may need a new washing machine box (the assembly with the hot and cold water shutoff valves) or individual valves.
• Hoses. Your washing machine should come with the correct hoses, but you can get them at most hardware stores. They use a standard garden hose fitting.
• Saw and/or tube cutter. You may need a saw to cut pipes and/or drywall for plumbing installation.
• Drill and mounting hardware. You may need masonry screws to mount the washing machine box or other fixtures.
• Protective gear. Work gloves, eye protection, and long sleeves can help prevent injuries.

Step 1: Gather your supplies.

The tools and materials you’ll need depend on the complexity of the plumbing installation. Determine how much of the plumbing is already in place and what you’ll need to install. Then, get all your equipment ready.

Step 2: Assess the location.

Most homes with an existing laundry room have a space designated for the washing machine. If you want your washing machine to go somewhere else, the installation may require more extensive plumbing work. You should also take this opportunity to measure the space and ensure your appliance will fit.

Step 3: Check for existing connections.

If you have an old washing machine installed, hooking up the new one is simply a matter of connecting the hoses and drain pipe to the existing fixtures.

Step 4: Shut off the water supply.

Before you begin any work on your washing machine plumbing, shut off the main water supply to your home. If you have the water running when you tap into the supply or drain lines, it can lead to flooding and water damage.

Step 5: Connect the water supply line.

To create a new outlet for the water supply line, you’ll have to cut the pipe using a saw or tube cutter. Add a tee fitting to run a supply stub out to the wall.

If running a new supply line is too complicated and you have a utility sink, a simpler solution may be to connect directly to the sink:

• Run a hose from the faucet using a sink aerator thread adapter.
• Because you'll use the faucet to adjust the water temperature, you only need to run the hose into the washing machine's cold water connection.
• Place a cap on the washing machine’s hot water connection.
• Place the drain hose into the sink to drain. These hoses usually have a hook-shaped end to hang on the sink rim.

Step 6: Connect fixtures.

Once you have a water supply stub in place, it’s time to install the appropriate fixtures. Use a drill and masonry screws to secure the washing machine box in place. Connect bibbs to the supply stub outlets so you can turn on the water and shut it off.

Step 7: Set up the drain.

Just as a rain pipe drains water from your roof to the drain, your washing machine uses a vertical pipe to drain water after washing. Similar to tapping the water supply line, you’ll have to run a drain line from the washing machine box. Be sure the drain hose isn’t obstructed or kinked.

Step 8: Install the vent system.

If you’re installing all new plumbing, you’ll also have to install a vent stack. The drain vent allows air to escape so air pressure can’t build and stop the water from draining. A clogged plumbing vent pipe can stop water from draining fully. Other signs that the vent is clogged are gurgling sounds or bubbling noises.

Step 9: Connect and test the washing machine.

Once you have the plumbing in place, hook your washing machine up to the fixtures. Turn the water on and run a light cycle to test the new plumbing.

When to call a plumber to hook up your washing machine.

Installing a new washing machine is a simple project, but installing washing machine plumbing typically requires the help of a professional. If your laundry room isn’t already equipped with a washing machine connection, you should probably call a plumber.

Thumbtack makes it easy to find a qualified professional. Download the app today to find a top-rated plumber near you.

Related: Why is my washer not draining?