How to Connect Washing Machine Waste Pipe to Sink

Water can back up into a sink due to a clogged washing machine drain pipe. In most cases, the issue isn’t with the machine itself but rather in its connection between sink and washing machine.

Connecting the waste hose from your washing machine to your sink is possible in several ways. The most popular is installing a standpipe, so any waste can be directed into main drainage outside.


Connecting a washing machine waste pipe to the sink is easy with several methods. The most straightforward is installing a standpipe, which can be done by either an experienced homeowner or professional.

You can also opt to replace the drain hose on your sink with an appliance nozzle, providing a more permanent connection between the sink and drain. Although this requires taking out the waste trap under your sink, the added peace of mind it provides is worth the extra effort.

To begin, measure and mark the section of drain pipe that requires cutting with a reciprocating saw. Make two cuts in the pipe, then fit a Y-fitting with its opening facing forward and parallel to the drain pipe.

When attaching the Y-fitting to two pieces of drain pipe, ensure the joint is square and cut away enough of the old pipe to clear it when finished. You can then clean away burrs with a utility knife.

Before proceeding, be certain the sink you are working on is connected to a P-trap. This prevents sewer gas from entering into your home and may be required by building codes or plumbing requirements in certain areas.

To ensure the effectiveness of a P-trap, it should be placed 6-18 inches above the floor and at least 2 feet from the wall. Additionally, place a screen inside the opening to collect lint and prevent pipes from becoming clogged.

Another option is to attach your washing machine drain hose to an outlet under your sink. This method works best when you only have one sink and is the most cost-effective way of connecting a hose to a sink.

If your sink has multiple basins, an appliance nozzle can be used to attach your washing machine drain hose to the spigot at the bottom. It may take some effort to get just right, but once done, installing drain pipe will be much simpler.


If your washing machine and sink drain into the same sewer pipe, your plumbing system could potentially experience clogs or backflow problems. Connecting the waste pipe from your washer to your sink can solve these issues by preventing backflow, conserving water resources and helping you steer clear of costly repairs.

You could disconnect your washing machine’s waste pipe from the kitchen sink and use it for other tasks, like emptying the trap or connecting your dishwasher’s drain pipe to that same sink. However, doing this is not advised as it could damage the plumbing in your sink and lead to backflow problems.

To prevent backflow from the washing machine, you need to ensure it’s connected to an appropriate standpipe assembly. This pipe connects your sewer or septic tank and installing a standpipe is the most secure way to stop backflow, but it can be challenging.

Install a proper waste trap for your washing machine and sink. These traps offer an affordable and straightforward solution to dealing with the waste generated from laundry equipment.

It is recommended to replace the trap if it becomes filled with dirt and other substances. Furthermore, remove lint from the trap and clean it regularly.

Furthermore, it’s essential that the waste trap has a secure seal. Otherwise, water could seep out and contaminate other areas in your home.

Next, you need to identify a section of waste pipe suitable for installing the Y-fitting. This requires cutting the drain pipe with a reciprocating saw.

Once you’ve cut the pipe, dry-fit a Y-fitting to both pieces of pipe. Make sure the opening of the Y-fitting points towards the front and is parallel with your sink’s waste pipe. Adjust its fit as necessary to create an optimal connection between washer’s waste pipe and sink’s waste pipe.

Once your new washing machine is connected to the sink’s waste pipe, all that remains is for you to do is attach a simple spigot and hose splitter. These items can usually be found at most hardware stores and require minimal effort for installation.


When renovating or replacing an existing washing machine, connecting it to the sink can be a tricky task. A bad connection could result in cross-connection, allowing contaminated water into your washer and resulting in dirty laundry for everyone.

To avoid this issue, a few key measures need to be taken. First and foremost, use a high quality standpipe with an adaptable spigot that can support some weight. Furthermore, make sure the spigot is positioned far down the drain in order for water not to overflow into the pipe or spill onto the floor.

Once you know the length of hose needed to connect to your new spigot, make sure it can support the weight without sagging. A quality waste pipe extension kit can come in handy here as it offers various tees and elbows tailored specifically for your installation.

It’s wise to attach the new spigot to the wall with two pipe clips in appropriate locations, ensuring vertical alignment and secure fit with screws and plugs. Applying high-grade silicone sealant around both the base of the clip and spigot itself can help prevent future leaks.


Sinks are water basins attached to walls or floors with a drainpipe. Sinks can either be natural, such as the bottom of a lake, or man-made such as your washing machine’s drain pipe.

When connecting a washing machine waste pipe to a sink, the most popular solution is using the spare spigot on your drain trap. This is usually an extendable plastic funnel that sticks out from the side and attaches your waste hose. Make sure to take off any blanking caps that might prevent use; these must be taken off before beginning installation.

When connecting the waste pipe to it, you must take into account the placement of the spigot. Make sure the waste pipe runs uphill after leaving the spigot as this will prevent water from going down the pipe and into your washing machine.

Ideal placement of your waste pipe should be such that its spigot is about 18 inches above the height of your p-trap. This is because p-traps are designed to prevent sewer gas from backing up into your drain line and into your home’s water supply.

When positioning your drain hose, another factor to consider is the height of your standpipe. According to UPC (Uniform Plumbing Code), a standpipe must extend at least 18 inches above your p-trap’s level.

Low-set p-traps can allow sewer gas to back up your drain and into your home’s water supply, potentially leading to a waterborne infection.

The same principle applies to the hose itself. W Service recommends that it be at least 30 inches high and ideally up to 96 inches. While this minimum requirement may not be necessary for solving your drainage issue, it will help ensure adequate coverage of your pipework.

The hose itself may seem like an ordinary connection between your appliance and the spigot in the drain trap, but it’s worth double-checking that there isn’t any kink or break in it as this could allow water to seep into the waste pipe. You can repair this with waterproof flex tape if necessary.

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