How To Connect A Laundry Sink And Washing Machine To The Same Drain

Most laundry room setups have one thing in common: both space and plumbing connections are too tight to fit two drains. That’s why people often have to choose between a laundry sink or a washing machine. Or do they? There’s good news – you can have both if you connect them to the same drain.

You can connect the laundry sink and washing machine to the same drain with a sanitary tee. In this way, you can link a sink drain pipe to the washer’s standpipe. Alternatively, you can choose to drain the washer directly into the sink.

3 Benefits Of Connecting Utility Sink And Washer To Same Drain

The main benefit of connecting the utility sink and washer to the same drain is the simplicity of the plumbing setup. You won’t have to add another drain line, which often translates into lower installation costs. But there are other benefits as well. Check them out below.

Fewer Backup Problems

No matter how careful you are, blockages can always happen on the washer drain line. For instance, you may have forgotten to place small laundry items (such as socks or underwear) in a laundry bag, and they get sucked in the drain.

A serious blockage could cause the water to turn back on the line and flood your laundry room. However, if you have a utility sink installed slightly lower than the washer, it could collect the water turning back and prevent messes.

You Can Rinse Clothes In the Sink 

Another advantage of having a utility sink in your laundry room is the possibility to rinse the clothes thoroughly if you accidentally use too much detergent.

Fewer Clogging Issues 

Lastly, you can use the sink to flush down the pipe things like lint and soap scum. When the fixture and the appliance share a drain line, the volume of water from the sink can help keep the pipes cleaner – provided that you don’t use the sink to wash down the draining stuff that could clog the pipes, such as paint products.

Things You Will Need To Connect Washing Machine To Sink Drain

Now that you know the advantages, it’s time to find out how to install the sink and washer on the same drain. Before getting started, gather the tools and materials below.

  • Waste Y fitting
  • Tape measure
  • Reciprocating saw
  • Utility knife
  • 90-degree elbow
  • 1/2-inch screws
  • 2 1/2-inch deck screws
  • 2-inch standpipe with trap
  • Primer 
  • Solvent glue
  • Protective equipment 

How To Connect Washing Machine Drain Hose To Sink

Connecting the utility sink and washer could seem intimidating, but most homeowners can carry out the project themselves. You’ll need some plumbing skills, but the steps below can help you accomplish your purpose, even if you’re a beginner.

Step 1 – Turn off the water supply and unplug the washer 

Inspect the wall behind the washer or under the sink to locate the shut-off valves. There should be three or four of them, depending on whether your washer is supplied with cold water only or hot and cold water. Turn all valves clockwise to cut off the water supply, then unplug the washer from the wall outlet (or turn off the electricity to the laundry room if your washer is hardwired. 

Step 2 – Measure and cut the sewer inlet pipe

Inspect the area under the sink and see if there is a sanitary tee or Y fitting already installed. If it is, you can skip this and the next step. Otherwise, measure the fitting and decide where is the best place to install it (consider the regulations in your area).

Cut the drain pipe with a reciprocating saw, then clean the burred areas with a utility knife. You could also sand the ends if you want to.

Step 3 – Install the Y fitting

Before attaching the fitting to the pipe, dry-fit it, positioning the opening parallel to the drain pipe and facing forward. Adjust the cut if necessary; if all is well, wipe clean the ends of the pipe and fitting, then use the primer and glue to attach the Y-fitting.

Step 4 – Install the standpipe

Once the glue is dry on the connection, dry-fit a 90-degree elbow from the Y fitting opening, then install a standpipe with a trap on the elbow.

Measure the distance from the floor to the top of the standpipe and place a mark at 34 inches – this is the minimum height recommended to prevent water backup.

Remove the pipes and cut the standpipe, then install them back again on the Y fitting, this time using primer and glue to fix them.

Step 5 – Connect the sink and washer 

Fit together the sink tailpiece and P-trap, then connect them with the sink inlet on the fitting you just installed. Fasten the connection with a ring nut or glue it with primer and plumbing glue. Once done, attach the washer’s drain hose to the top of the standpipe and secure it with a hose clamp or plastic tie. 

Turn on the water from the shut-off valves and plug in the appliance. Run an empty cycle and let the faucet run for a few minutes to check for leaks and control drainage. That’s it.

Frequently Asked Questions

Connecting a sink and washer on the same line is possible and wise, but you may still have questions. Find out some answers below.

How far can I extend my washing machine drain hose?

It is hard to tell, as it depends on your space while also taking into account the code in your area. Generally, you shouldn’t use a hose longer than 8 feet.

What is the plumbing code for washing machine drain?

According to the Uniform Plumbing Code, the standard for washing machine drain size is 2 inches. The P-trap should be between 6 and 18 inches high from the floor, while the pipe should be between 18 and 30 inches high from the floor.

Wrapping Up

Now that you know how to connect a laundry sink and washing machine on the same drain, all you have to do is decide the laundry room layout and get to work.

Have you ever done any plumbing yourself before? Will you carry on this project yourself or hire an expert? Tell us in a comment.

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