Basement Drain Backing Up When Washing Clothes?

Last Updated on October 22, 2021 by Kimberly Crawford

It is always a laundry hassle whenever the drain starts backing up. It is especially risky for basement laundry rooms to have this problem because overflows like these raise the moisture level of the basement.

You do not want this to happen if you have wood structures around and of course, it is kind of messy when your basement drain is backing up when washing clothes. 

The fortunate news is that this is a normal case scenario in drains. But when this happens, it would pay to know the steps you can do. This post rounds that up for you so read on. 

Why does my laundry room overflow? 

basement leaking water

There are two major reasons as to why laundry rooms experience overflow. The first one is when the washing machine’s drain hose has a leak or is completely damaged and second is when there is a blockage or damage in the laundry room’s floor drain. 

What causes basement drain backing up when washing clothes? 

There are a lot of things that might end up causing basement drain to back up when washing clothes. It pays to know where the source of the backing up is coming from so that you can make the necessary interventions before they could cause more trouble. 


The most common cause of basement drain backing up when washing clothes would be a blockage. Specifically, it might be caused by a clogged drainpipe. In some instances, the blockage may also be caused by having a very small drainpipe requiring you to replace it soon. 

Another reason for blockage would be the pressure from the washing machine. Because of the hard pressure and resistance of the basement drain sucking the water in supposedly, backflow happens. If you suspect that one of these might be the cause of the blockage, you can easily use an auger, drain bladder, the famous Drano, or a hose. 

Excess water

This is not a popular fact but too much water can also cause the basement drain to back up when washing clothes. A washing machine runs 30-40 gallons of water every time you wash.

If the pipes are not in good shape or are already old, the high volume of water will cause the basement drain to back up. When this happens, having the pipes snaked could be the best intervention. 

Plumbing vent pipe

The plumbing vent pipe is attached to the roof that is why most homeowners would not think that it might be the cause of the basement drain backing up when you wash clothes. Since it is connected to the home’s drain line, any clog or blockage in it shall cause an overflow in the drain. As such, make sure that debris, leaves, and other sources of blockage make it to your plumbing vent pipe.

Why is there a smell when the basement drain backs up? 

There is no one way to answer this so in here, we will provide a handful of answers. It is not just the overflow that can cause massive problems for the homeowner because the bad smell that comes from the drain gives more hassle. 

As soon as you encounter that bad smell, it is already signifying that your drain has dried out. By drying out we mean that the traps set to filter and drain the water are already broken.

When there are no traps inside the drain, the sewer odor comes out leaving that repulsive smell in the basement laundry whenever the water backflows from the basement drain. 

How do I immediately handle a basement drain backing up? 

basement laundry room leaking

There are some safety measures that you must put into mind when a basement drain starts backing up. The basement laundry room is still connected to an electricity circuit and there are also soft wood structures and furniture that must be taken cared of or must be put somewhere else. 

When backflow in the basement drain happens, here are the tips that you should remember: 

  • Turn off appliances and the main fuse to avoid electrocution in the flooded area. 
  • You may also shut off the main water line if you are not sure yet about what is causing the basement drain to back up. 
  • If your basement shelters a laundry room and a bathroom, it is best not to use the sink or toilet while the water is backing up because your water use might add to the sewer’s load. 
  • If sewage odor comes off while the basement drain is backing up, wear gloves and face masks before doing any sort of de-clogging. 

Related: How To Clean Up Flooded Basement

How do I stop my basement floor drain from backing up? 

If you want a more permanent fix in preventing basement drains from backing up while you wash clothes, here are some small devices that you can install literally down the drain. 

  • Backwater check valve: They also go by the name knife valves and they are usually installed by the holdout in the basement’s floor. When it is closed, no water will flow in the toilet and the sink. At the same time, it will also inhibit sewage backflow. 
  • Backflow plugs: These types of devices are not just easy to install but also works simply in inhibiting backflow. They are equipped with plastic balls on their tips that will float and act as barriers to the drain, preventing backflow. 

There are different types of backflow plugs and different homes might require a specific type. For some heads up, here are the types of backflow plugs: 

  • Twist plugs (which can come in plastic or metal forms)
  • Ball plugs (which are the most conventional and most common)
  • Pressure plugs (usually made of wood or plastic)
  • Threaded caps (which are used to cover pipe endings)

Aside from these small device installments, hiring a plumber occasionally for checkup is also a good idea to stop the basement floor drain from backing up. Following the three-year valve replacement might also be something to consider. 

Related: How to Unclog A Toilet When Nothing Works (9 Methods)

Can I count on home/DIY solutions in unclogging my basement drain?

They say that unclogging the basement drain to prevent backing up need not be expensive. If you are considering going down this route, you must know that they also come with some drawbacks. The most common home solutions used in de-clogging would be vinegar, baking soda, Coca-cola and Drano (or similar products). 

The main de-clogging component of these products would be their acidity. While it is true that they are fast de-cloggers, it is also a fact that they leave residues behind. Most of the time, these residues become the main reason of clogging in the long run as they accumulate at the bottom of the sewer line. 

How much does it cost to unclog a basement drain?

Unclogging the plumbing pipes could cost a lot especially if you consult plumbing professionals. The rate is per hour and depending on how much debris there is, or the extent of damage on the drainpipe, the labor cost is at a range of $70-120

If you wish to do it yourself, you can buy plumbing snakes at $25-50. But if the clog runs deep, you might want to consider buying a drain auger at an average price of $250-700.

Since the price could be daunting at a one-time-big-time de-clogging project, you might just consider having it cleaned and inspected once every three months. This would only cost you $80-150. 


At first, basement drain backing up when washing clothes could look harmless, disguising as a small leak or just a circumstantial overflow. As soon as you spot water backflow by the drain, you should start inspecting your basement drain for some clogs.

It could be anything from accumulated fabric to debris but if you are not attentive, it might cost you a lot to have it fixed.