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How to Troubleshoot a Dishwasher That Won’t Drain: A Step-by-Step Guide
Plumbing-Related Drain Problems
Dishwashers often fail to drain due to plumbing issues outside the appliance itself. Check the following:
- Garbage Disposal: Ensure it is clear of food buildup. Run the disposal thoroughly with plenty of water to resolve potential drainage problems.
- Air Gap: Clean the air gap and the hose connecting it to the disposal or sink drain to remove any blockages.
- High-Loop: Inspect the dishwasher’s drain hose. If it is not looped up higher than the level of the dishwasher, water may not drain properly. Return the hose to its proper position or install an air gap.
Appliance-Related Drain Problems
If plumbing issues are not the culprit, consider the following appliance-related causes:
- Drain Screen: Check for clogs in the drain screen at the bottom of the dishwasher tub. Remove any obstructions, such as plastic lids, glass, or labels.
- Filter: Clean the dishwasher filter according to the appliance manual’s instructions. Different models may have screens, removable filters, or require removing the bottom spray arm for cleaning.
- Dishwasher Drain Hose: Disconnect the drain hose from the dishwasher pump. Clean the end of the hose and blow into it. If it is clogged, remove the clamp on the other end and clean the hose in a sink. If unclogging is unsuccessful or the hose is old and cracked, replace it.
When to Call a Professional
If your dishwasher is relatively new and the above fixes have failed, consider the following:
- Dishwasher Replacement Parts: Check for faulty dishwasher components such as the check valve, piston and nut assembly, drain pump and drain motor, pump solenoid, belt (on belt-driven pumps), timer, door switch, or electronic control. These parts are widely available online.
- Electrical Expertise: Checking many of these parts requires a multimeter and knowledge of electrical circuitry. It is advisable to leave this task to a professional unless you possess the necessary expertise.
Additional Tips:
- If you have just installed a new garbage disposal, make sure the plug inside the drain hose nipple has been removed.
- Regularly inspect the dishwasher’s drain hose for kinks or blockages.
- Clean the dishwasher filter regularly to prevent clogging.
- If the dishwasher is not draining properly after a cycle, check for any remaining water at the bottom of the tub. A small amount of water may be normal, but excessive water indicates a drainage issue.
- If you are replacing a dishwasher, some appliance stores offer free installation and old appliance disposal as part of the purchase price.
