When your dishwasher won’t drain on its own, you can come to the rescue—once you know the common causes and solutions.
There’s usually no preceding or noticeable event. No big show of, “Wow, that’s broken!” Rather, it’s just one of those annoying little surprises of homeownership: One day, all’s fine with your dishwasher; the next, there’s standing water pooling in its basin.
The good news is that it may be a simple clog or loose connection that can be quickly remedied.
Steps for Fixing a Dishwasher That’s Not Draining
“Simple” fixes are made simpler by being prepared. Before getting started, gather all the tools you might need (which may include a flashlight, rags, and a bucket, bowl, or baking dish). Empty the dishwasher of dishes, cutlery, and racks (some top racks have retainer clips; others lift out like drawers) and remove items from underneath the sink.
Use the Model Number and Live Chat
Determining how to drain a dishwasher depends on the source of the clog.
First, find the dishwasher’s model number, usually labeled on one of the door panel edges.
With the model number in hand, troubleshoot by consulting the manufacturer’s website. Whether you need to order a part or “live chat” with someone, nothing can happen without the almighty model number.
Check the Drain Hose Attachment
Though the bottom of your dishwasher is below your sink drain or garbage disposal, the dishwasher drains upward into the sink’s discharge port or disposal, propelled by a built-in impeller pump.
The first thing to check if the water is not draining from the dishwasher is the “drainpipe” from the dishwasher to the disposal.
Terminology note: The word “pipe” almost surely refers to a flexible tube commonly called a discharge or drain hose. This tube—or hose—has rubber fittings on each end. End 1 is affixed to the dishwasher itself and may require pulling the unit out of its location to access it. End 2 is affixed—probably by pipe clamp—to the sink drain discharge port or disposal.
Remove End 2 and check that it’s clear of debris, so have a rag on hand. Also, check the fitting on the discharge port or disposal itself. Make sure this is unobstructed and reasonably muck-free.
Finally, the tube itself—especially if it is corrugated or ribbed—may simply have accumulated years of food waste. If this is the case, clearing it with a wire or coat hanger may work, at least to get you through a holiday. However, long term, it may be best to replace the dishwasher drain tube.
Make sure, too, that the hose isn’t jammed by a poor installation in the first place or kinked by items that have accumulated under the sink. If you can, position the tube so it is above the entry point into the discharge port or disposal.
If you have a new disposal, it’s possible its drain plug hasn’t been removed. If you suspect that’s the case, remove the drain tube, knock out the drain plug, replace the drain tube, and run a quick cycle.
The discharge hose may also be kinked behind the dishwasher in the cabinet, and you may have to uninstall and pull the unit out to access it. (Being conversant with the steps on how to install a dishwasher might come in handy here.)
Check the Filter
Dishwashers have varying types of filters and drain assemblies, but all filters sit in the bottom of the dishwasher basin and can be clogged with undissolved detergent, food scraps, product labels, and any other non-soluble matter that makes it from plate to dishwasher.
Check out the directions in your dishwasher’s manual and learn how to remove the filter on your unit—you may need a few different driver tips for your screwdriver, or none at all. Follow the instructions for cleaning. Usually, all it takes is a soft-bristle brush to remove debris. Reinstall and test out a quick run cycle.
If the clog is inside the drain filter compartment (which may have a secondary filter) you can try to dissolve it with a 50-50 blend of vinegar and baking soda, a homemade non-toxic drain cleaner that’s easy on parts. Let it sit in the drain filter area for 15 minutes, rinse with hot water, and run a quick cycle to see if out any the blockage has cleared.
Filters should be cleaned from time to time, depending on your dishwasher’s frequency of use. Clogged filters can slow the system’s water and result in less effective dishwashing.
Check the Drain and Valves
Perhaps your dishwasher won’t drain because of a problem with its drain or check valve. A dishwasher’s drain valve is an electrical part that may have a visible, movable bracket or arm. This is accessible by removing the unit’s front panel and placing it on the floor.
The bracket should move easily. However, it may be frozen in place or otherwise jammed. If you can free it up manually, that may solve the problem. If it won’t move, however, the problem could be electrical, and a new valve may be needed.
A check valve is a mechanical element that allows water to pass in one direction—out of the dishwasher—but not back in. It can be a small flapper or ball at the beginning of the drain tube, right past the drain valve. A check valve can become stuck, and will either need to be reset, freed up, or replaced. Access to the check valve is also through the front of the unit.