Diagnosing Washing Machine Drain Problems

Washing Machine Spills Soap
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Drain problems with a washing machine fall into one of two categories: either the water will not drain out of the washing machine itself,  or water does leave the machine but cannot flow properly through the drain pipes. A number of different specific problems can cause these general issues, and diagnosing them can be a tricky business. Some of the problems you can fix yourself, while others will most likely require a call to an appliance repair person.

Diagnosing the Problem

First, make sure to consult your washing machine's owner's manual. The troubleshooting section may give you suggestions for likely reasons for drain problems. Some modern washing machines display error codes that will identify the problem for you. If this doesn't identify the problem, observe your washing machine as it runs through one of its drain cycles. As you watch the machine in action, one of the following problems will likely be identified:

  • Clog in the rubber drain tube leading from the washing machine to the drain standpipe
  • Material obstructing the water pump filter or impellers
  • A mechanical failure of the water pump 
  • Loose or broken drive belt
  • Faulty lid switch
  • Clog in the drain system

Drain Hose Problems

If you hear the washing machine's pump operating but no water is leaving the machine, it is likely that the rubber drain hose running from the back of the machine to the drain standpipe or washtub is clogged with cloth fibers.

This can sometimes happen after you wash items like rugs, which may shed a lot of fabric fibers, or if the drain hose is pinched. If the tube is clogged, it can prevent the water from being pumped out of the machine.

To test this, remove the drain tube attached to the washer and make sure it is clear.

An easy way to check that the drain tube is clear is to blow air through it. If nothing is obstructing the drain tube, the problem is most likely at the washing machine pump. If the hose is worn or badly kinked, replacing the hose may improve the ability of the machine to pump water. 

Drain Pump Problems

If you can hear the pump operating but it sounds like it is laboring, there may be a piece of fabric or another item obstructing the pump mechanism. To remedy this, you'll need to shut off and drain the machine and remove the washing machine panel to examine the water pump. The pump itself may be clogged, or the clog might be in the corrugated tube that leads to the pump. 

Most pumps have removable covers, and inside you will find a filter screen on the pump. If this screen is clogged with debris, cleaning it and reassembling the pump will likely fix the problem.

On top-loading washing machines, the pump is usually located on the back of the machine; on front-loaders, it is usually found on the front of the machine, below the door. ​Remove any visible lint from the filter screen and rinse it in water. Also, check the impellers on the pump and make sure they move freely and are not jammed with any obstruction.

Reassemble the pump and cover panel, then test the machine.

If the pump is making no operating noise at all, or if you find no obstructions in the pump or drain hose, it is possible that your water pump has failed and will need to be replaced. This is normally a job for an appliance repair person, although it's possible for a skilled homeowner to order the part and perform the replacement. 

Drive Belt Problems

The pump is operated by a drive belt that fits around pulleys on the bottom of the washing machine motor. If this belt is broken or isn't tight on the pulleys, the washing machine will have difficulty draining or may not drain at all. Fixing this will require you to turn machine be over on its side to examine the belt. Homeowners can do this themselves, although many opt for having a repair person handle a repair of this level.

Lid Switch Problems

Just under the lid or door on the washing machine, a small plastic switch serves to sense when the door is shut so the machine can operate. If this switch is faulty, the machine may fail to drain correctly. With the door open and the machine running, press the switch by hand and listen for a clicking sound. If you don't hear it, the switch may need replacing. 

Plumbing System Problems

If water is successfully pumping out of the machine but is then spilling out of the drain stand tube or backing up in the washtub, then the problem is likely a traditional drain clog. Because small fabric fibers routinely are flushed through the system, it's common for drain clogs to occur in the plumbing pipes into which the washing machine drains. A clogged drain causes water to back up into the standpipe and spill on the floor. Clearing the clogged drain will usually resolve the problem.

The washing machine drain hose goes down about two feet into the plumbing drain standpipe. (In some machines, the drain hose may simply be clamped onto the side of a wash tub, though this is not an acceptable practice anymore.) From there, the water then goes into a drain trap. The clog could either be in this trap area, or it could be further down the drain line.

To determine where the clog is located, first, fill the washing machine with water. Turn the dial to the spin/drain setting and get ready to drain it. Position yourself where you can see the drain standpipe while still having access to the washer dial. What you're looking for is how long it takes the water to back up and out of the drain pipe.  Note: Be ready to stop the washing machine from draining at any moment.

  • If the washer backs up in just a few seconds, then the clog is likely very close and can be cleared with a small power drain snake operated down through the standpipe. You may even be able to clear it with a small hand-operated snake.
  • If the drain takes some time to back up, then the stoppage is likely quite far away. In this case, you will need to use a medium drain snake through a clean-out to clear the stoppage.

    Most people do not own the drain snakes necessary to clear these kinds of stoppages. Fortunately, they can be rented by the hour from home improvement and tool rental stores if you decide to do it yourself. Often there is a clean-out fitting behind the washing machine that can be used to snake the stoppage.