How Does My Dishwasher Drain?
To get started on solving your dishwasher problems, you need to find out what type of drain system your dishwasher has. You will need to look in the kitchen cabinet below the sink and see how the dishwasher drain hose connects to the drain. Below are the four most common types of drain systems.
High Loop Drain to Garbage Disposal
The dishwasher drain hose comes through the cabinet from the dishwasher and rises to the upper part of the cabinet. It is secured there and then connects down to the disposal intake.
High Loop to Drain Pipe
If you don’t have a garbage disposal installed, the dishwasher drain pipe will still have a high loop present, but instead will connect directly to the drain pipe. The connection must be above the drain’s P-trap to avoid having sewer gases from flowing into the dishwasher and causing severe odors.
Air Gap Cylinder to Disposal
In some areas of the country an air gap cylinder is part of the plumbing code for dishwashers to have. In this type of drainage hook up, the drain hose enters as before, but will attach to the air gap cylinder mounted on the back of the sink. The cylinder regulates airflow and helps prevent the hose from getting airlock and becoming clogged.
Air Gap Cylinder to Drain Pipe
This setup is the same as mentioned above, except that there isn’t a garbage disposal to attach to. Instead the hose from the air gap connects to the drainpipe before the P-trap.
Seven Causes of Drainage Problems
Clogged filters, blocked hoses, even old faulty pipes can all contribute to your dishwasher not draining properly. Below are seven common dishwasher issues that cause drainage problems.
Dirty or Clogged Filter
Dishwashers handle food debris in one of two ways; with a filtration system or a hard food disposer. Filtration systems collect whole food particles in a mesh basket in the bottom of the dishwasher. Units with a hard food disposer will automatically grind up the leftover food with a chopper. If you have a dishwasher with a filtration system and don’t wash all of the food off of the plates before loading into the dishwasher, this can lead to drain backups and standing water in the dishwasher tub.
Using the Wrong Detergent
It is important to use the proper type of dishwashing detergent for your machine. Most dishwashers today work best with powder rather than liquid. Using liquid can lead to adding a bit too much to the dispenser, leading to excess sudsing and then inadequate draining. Please refer to your owner’s manual for the correct detergent recommendations.
Blocked Garbage Disposal
Garbage disposal blockage can lead to your dishwasher not being able to drain out properly. It is important that your disposal be operating correctly as to avoid problems down the line. Sometimes just running the disposal empty for a brief moment can clear any blockage. Also using cold water while operating will help keep grease from forming any clogs.
A Clogged Air Gap
If your dishwasher has an air gap cylinder, over time it can become clogged with grease and other obstacles. Using a tweezer and a small brush can usually clear the airway. After cleaning, run your appliance for another cycle to see if this resolves the problem.
Drain Hose Clogs or Kinks
Just as a kink in your garden hose will cause problems, the drain hose for your dishwasher can suffer the same situation. Whether from improper installation or simply time taking a toll, any type of blockage or twists in the drain hose will prevent proper drainage and potential backup. Inspect the hose to make sure it is properly supported and doesn’t have any twists that can cause problems.
Faulty Drain Hose
If your drain hose appears to be clear of obstruction and twists, there may still be problems to discover. For example, an older rubber hose may have cracks and tears along the length or at connection points due to age. A visual inspection can reveal these types of issues and a replacement will be necessary. While not expensive, the labor aspect may be more than you want to take on. Please consult a professional if you have any hesitation before attempting this repair.
Old Plumbing and Pipes
If you have tried the suggestions mentioned above without success, then it may be time to take a look at your plumbing situation on a larger scale. Are the pipes in your home old or in bad shape? It may be time to consider a plumbing remodel, at least for your kitchen area. The cost may be significant and will be based on the type of new pipes that you use, along with a labor cost. Due to the intensive nature of this repair, it is best to have professional contractors do the work for you.
Troubleshooting the Drain Problem
Here are a few steps you can do to try and troubleshoot where your drainage problem may be.
- Run your garbage disposal. Dishwasher that filter food to the disposal can become clogged at times. Simply running the unit can often clear any clogs and help with dishwasher drainage.
- Drain the water from the dishwasher and run another cycle. The prior cycle may have been interrupted, causing the water to not drain properly.
- Clean the drain filter. Refer to your owner’s manual on the proper method of removal and cleaning. A clogged filter can cause improper draining.
- Clean out the air gap cylinder. Often overlooked for clogs, this can cause a dishwasher to back up. Remove the cover and cap to visually inspect for any blockage. Remove any impediments with tweezers or a thin brush.
- Run another dishwasher cycle with vinegar. If you have found debris in your unit, you can clean it out by running a cycle with a cup of white vinegar in the upper rack. This will help to dissolve any remaining residue and buildup that may linger.
Prevention and Professional Help
To avoid potential drainage problems, there are a few simple maintenance steps that you can do to keep your machine working at its best.
- Unless your dishwasher has a hard food disposer, it is a good idea to rinse your plates clean of food particles before loading in the racks.
- Use the proper temperature setting for the dishwasher cycle.
- Make sure the food filter is clear of any debris that may be ready to clog up the drainage system.
- Use the proper type of detergent as recommended by the manufacturer.
- Regular use will keep parts and plumbing in working order.
If the situation is beyond your skill level, you should call in a professional plumber to manage the situation. A faulty DIY repair may lead to a more expensive service call later. If you find you need a new dishwasher, consult our guide Things to Know Before Buying the Best Dishwasher for Your Kitchen. Also, Lowe’s has appliance delivery, installation and haul away for your new dishwasher if needed.
Frequently Asked Question
Here are answers to some of the most commonly asked question of dishwasher drainage problems.
Why is there standing water in the bottom of my dishwasher?
Standing water in your dishwasher that is present after a wash cycle has run is an indication of a clog or blockage problems somewhere along the drain system. Consult our article for remedies and potential fixes for this problem.
How do you fix a dishwasher that won't drain?
Fixing a drain problem in your dishwasher can be done in one of several ways. It can be as simple as a clogged drain, a blocked drain hose or a more difficult issue like a clogged garbage disposal. Refer to our article for more details on ways to identify and correct your drainage problems.
What are some common causes for my dishwasher not draining?
Clogged filters, blocked hoses, even old faulty pipes can all contribute to your dishwasher not draining properly.
How do I force my dishwasher to drain?
There isn't a proper way to force your dishwasher into a drain cycle. If you suspect your dishwasher is having a drain issue, refer to the suggestions in our article on how to locate the problem.