Is It Possible For Washing Machine Drains Into Sink?

Washing Machine Drains Into Sink

There’s no harm in washing machines sharing the drain with the utility or kitchen sink. The utility sink and washing machine can drain to the sewer line through the common draining system. It works fine unless one starts backing up to boost your frustration.

Thus, you must understand the working system of the washing machine drain into the sink and why it is backing up. Once you identify the reason, you may fix it to help your washing machine and sink drain properly.

When the washing machine drain hose to sink fails to work, there are two reasons. It happens because of improper venting and blockage inside the pipes. Thus, you have to observe the entire draining system to find the reason. If the water is restricted due to blockage, you might use a plunger to remove the clogs from the pipe.

Washing Machine Drains Into Sink: Is It Possible?

Did you install a washing machine in your basement without a proper drainage system? Then, you can drain it differently. You can use a hose to connect the utility sink with the washing machine. Thus, both the sink and washing machine drain into the same plumbing system.

However, you will need a special hose for this purpose. It will also depend on the distance between the appliance and the sink. Thus, when looking for a washing machine drain hose to sink, you may look at the following options.

  1. The rubber drain hose is an affordable alternative. It can connect your washing machine with the main draining or utility sink. A newer rubber drain hose has rayon or braided mesh to strengthen the hoses.
  2. Do you want the absolute best drain hose for connecting washing to the sink? Then, you should choose the braided stainless steel washing hose. It can tackle the workload to drain the larger washing machines perfectly.

When you connect the sink and washing machine with the hose, you must also secure it. At the backside of your sink, mount the wire ties to secure the washing machine drain hose. Or, you may install the traditional brackets.

Since the drain hose may get clogged and start backing up, you may install a homemade filter at the drain hose end. However, the hose may still back up and cause overflows. Then you need to identify the reasons.

Why Is My Washing Machine Draining Into My Sink?

You can get panicked when you see the washing machine draining into the sink instead of draining into the main sewer line. Also, you may get panicked if you see the washing machine water back up the kitchen sink or utility sink.

When you see such happenings, you must observe the system and try to find the problem. Usually, the water from the washing machine hose will drain into the sink instead of the main one. It happens for the following reasons.

Clogged Drainage Pipe:

Do the washing machine and utility sink share the common drainage pipe? If yes, then clogs can often stop the system from working properly. We wash many things in the utility sink. So, this leads to gunk, residue, and other debris developing inside the draining pipe.

Nonetheless, you must observe and locate where the clog has happened. Usually, you will find two locations of the clogged draining pipe.

  1. The clog has happened before the utility sin. It happens when you see that the water is backing up from your washing machine drain.
  2. You see the water backing up in the lowest fixtures. The problem is right after the utility sink and washing machine hose connection.

You may use a plunger to eliminate the problem when you find the clogs. We will discuss it in the following section.

Problems in the Vent:

The vent is responsible for providing enough air supply to the drain and water line pipes. It helps to transfer the water through them. When there’s a problem with the venting system, it affects the drainage system of your appliance and utility sink.

The easiest way to identify the problem with the vents is to observe the sound. Observe it when the water drains through the pipes. If there’s any problem within the vent pipes, you will hear a loud gurgling sound. The vent fails to supply adequate air pressure if you have installed the wrong size vent. Also, maybe one side of the vent has been plunged. Usually, when you have a large washing machine and undersized vents, you experience such problems.

Also, birds’ nests or debris on the vent opening will prevent the air from flowing through the vents. It will result in the lack of the right air pressure to the main draining pipe. It is a problem because through it your utility sink and washing machine will drain.

Problems with the Drain:

Finally, when you see the washing machine draining into the sink and backing up, the problem might be the drain itself. A standard washing machine will pump 15 gallons of water through the drainpipe. The draining rate will increase with the size of your washer and the washing speed you have set with the device.

Thus, you need the right-sized draining pipe. it will tackle the increased draining rate of the appliances. Technically, a drain pipe needs to be at least 1-1/2 inches in diameter. Only then, it will drain the washing machine water properly. Nowadays, many building codes need you to install a 2-inch drain pipe. Thus, these home appliances help them drain appropriately.

Therefore, when you see that the water is backing up instead of draining, you must check the drain pipe size. If it is undersized then the suggested one, you may need to replace it. You will have to call a plumber because changing the drain pipe will require you to remove and redo the drywall.

How Do I Stop My Washing Machine Backing Up Into My Sink?

When you see the washing machine backing up into the utility sink, you need to fix it ASAP. Otherwise, you will see water flooding the floor. The steps to stop the water from backing up from the washing machine include the following.

Method 1: Remove the clogs

In most cases, water from the washing machine backups instead of draining into the main sewer line due to clogs in the pipe and p-trap. Thus, you will need to unclog the pipe.

  1. Start by identifying where the clog has occurred. When you have observed where the clog has happened, you need to clear it.
  2. You may use a plunger to unclog the P-trap and drain pipe. Also, if the clog is too deep down inside the pipe, you will need to use a long plumbing snake.
  3. Turn off the main water line before you use the plunger or plumbing auger. Also, turn off the utility sink faucet.
  4. Now, wait for a few moments so that there’s no water inside the main supply line. Now, you need to open the stopper of the utility sink to access the drain pipe.
  5. The stopper of the sink will be connected with bolts underneath the sink. So, reach beneath the sink and remove the bolts using an Allen wrench or screwdriver. You can insert the plunger inside the draining pipe when you have removed the stopper.
  6. Continue inserting the pipe unless it gets stuck with the clogs. Now, turn the plunger or plumbing snake to collect the clogs. You will need to repeat the process of inserting the plunger and collecting the clogs until it is fully cleared.

You can reinstall the stopper and turn on the waterlines when you have removed the clogs.

Method 2: Fix the vents

If the washing machine is backing up due to the problems with the vents, you will have to fix it. However, fixing the vents may not be a cup of tea for most homeowners. Thus, we suggest you call a professional for it.

The vent may sometimes have a vacuum due to debris and residual build upright on its mouth on your rooftop. So, you need to check the opening of the vents on your roof. There might be debris or even the bird’s nest. You need to remove the bird’s nest or residual build-ups from the vent opening to help air pass through it properly.

Lastly, if you have a wrong sized vent, you may need to replace it, and it can be costly.

Frequently Asked Questions:

Can a washing machine and sink share a drain?

Yes, a washing machine and sink can share the same drain, and vent lines are located closely. You can tie the washing machine hose securely to the sink with a tie wire.

Can washing machine waste go into sink waste?

Yes, you can connect the washing machine right with the waste trap of your kitchen sink. You need to ensure that the waste trap isn’t clogged and working.

Does a washing machine drain need to be vented?

Yes, you must install the vent for your washing machine drain also. It is part of the building codes and plumbing prerequisites in many regions. Also, you need to mount the vent for the washing machine drain to help the water flow through the pipe properly.


When the washing machine drains into the sink, you can easily secure the connection. Also, if you see the water from the washing machine backing up, you must unclog the drain pipe. Also, you will need to check and fix the vents. It is common to have a few issues with the plumbing system of your washing machine once in a while. You can fix it following our suggestions above.

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