How To Hook Up Washing Machine Plumbing

Setting up a washing machine is more than just plugging it in and connecting a few hoses. In the video above, This Old House plumbing and heating expert Richard Trethewey shows a homeowner how to hook up washing machine plumbing. We’ll go through the process in detail below, from preparing your space to testing the installation.

Tools Needed for This Project

Preparing the Space for Washing Machine Plumbing

Before you start, clear out the area where you’ll be working. If you’re replacing an old washer, unplug it and carefully move it out of the way. This gives you room to work, access the plumbing connections, and see what you’re doing.

Building a Support Structure

A strong base for your plumbing connections can make your setup more secure and look better. Here’s how to build a simple support against a wall:

1. Measure and cut wooden studs to fit the height of your wall.
2. Secure top and bottom plates to the floor and ceiling.
3. Install vertical studs between the plates, spacing them evenly.
4. Attach a plywood panel to the upper half of the wood stud wall using 1 5/8-inch screws.

This structure creates a solid backing for mounting your plumbing components and helps protect the pipes from damage.

Installing Water Supply Lines

Now let’s look at how to run new hot and cold water lines to your washer.

Running Copper Pipes

Copper pipes are a popular choice for washing machine plumbing because they’re durable and resist corrosion. Follow these steps to install them:

1. Turn off the hot and cold water leading to the washing machine.
2. Clean the outside of the pipes and the inside of the fittings with a cleaning brush.
3. Measure and cut copper pipes to the needed length using a tubing cutter.
4. Apply flux to the cleaned areas as a seal for soldering.
5. Solder the pipes and fittings together using a propane torch. Be sure to apply heat evenly.
6. Allow the soldered joints to cool before moving on.

Installing the Washing Machine Valve

The washing machine valve allows you to control the water flow to your washer. Here’s how to install it:

1. Attach the valve to the ends of the hot and cold water pipes.
2. Verify that the valve is in the “off” position before connecting it.
3. Use rubber washers to create a watertight seal between the valve and the pipes.
4. Tighten all connections securely, but be careful not to overtighten and damage the components.

Trethewey recommends turning off the washing machine valve when you’re away from home to relieve pressure on the hoses and prevent potential laundry leaks. If you are also planning on hooking up or adding a utility sink to the laundry supply lines, plan for that as well when installing the water lines.

Connecting the Washing Machine

With the plumbing infrastructure in place, you’re ready to connect your washing machine.

Attaching Water Supply Hoses

Trethewey emphasizes the importance of using high-quality washing machine hoses for your connections. He replaces old rubber hoses with braided stainless steel hoses for added durability and safety. Follow these steps to attach them:

1. Connect the hot water hose (typically red) to the hot water valve on your washing machine and the corresponding hot water supply valve.
2. Repeat the process for the cold water hose (typically blue), connecting it to the cold water valve on the machine and the cold water supply valve.
3. Tighten all connections securely by hand, then give them an additional quarter turn with pliers.

Positioning the Drain Hose

Putting the drain hose in the right spot helps your washer drain well and prevents washing machine drain overflows and backflow. These are the steps:

1. Insert the drain hose into the standpipe, making sure it doesn’t extend too far down. We recommend extending the hose about 4–6 inches into the pipe.
2. Check your washing machine’s manual for any special instructions.
3. If needed, use a cable tie or hose clamp to keep the hose in place.

Testing the Washing Machine Plumbing Installation

After completing the installation, it’s time to test your work. Make sure that everything is functioning correctly and that you have no leaks.

Checking for Leaks

Follow these steps to check for leaks in your newly installed washing machine plumbing:

1. Turn on the main water supply to your home.
2. Open the hot and cold water valves for the washing machine slowly.
3. Inspect all connections, including the washing machine valve, hose connections, and pipe joints, for any signs of leakage.
4. If you notice any leaks, tighten the connections or replace faulty components as needed.

Also consider adding a washing machine drain pan to protect against leaks in the future.

Running a Test Cycle

To make sure your washing machine is working well with its new plumbing, try this:

1. Plug in the washing machine and turn it on.
2. Run an empty cycle using a small amount of detergent.
3. Watch the machine as it fills with water, agitates, and drains.
4. Check for any unusual noises, vibrations, or water leaks during the cycle.
5. Inspect the area around the machine and the drain for any signs of water after the wash cycle is done.

If you run into any big problems—or if you’re not sure how to fix something yourself—call a professional plumber for help.