Dishwasher Not Draining? Causes and Fixes

Opening the dishwasher to find a pool of dirty water at the bottom is unpleasant, but it is also one of the most fixable appliance problems. Many draining issues come from a clog you can clear yourself in a few minutes. Here is how to work through the likely causes, from easiest to hardest.

Safety first

Before you start:

• Turn off power to the dishwasher at the breaker or unplug it.
• Protect the floor with towels.
• Remove standing water with a cup and a sponge, or use a wet-dry vacuum.

Never reach into the bottom of a dishwasher with the power on.

Check the filter

The filter is the most common cause of a dishwasher that will not drain. Many modern dishwashers have a manual filter that needs regular cleaning.

1. Remove the bottom rack.
2. Find the filter assembly in the floor of the tub, often a cylinder that twists out.
3. Remove it and rinse it under warm water. Use a soft brush to clear trapped food and grease.
4. Check the area underneath for bits of glass, bones, seeds or labels.
5. Reinstall the filter securely.

Your owner's manual will show the exact steps for your model and how often to clean it.

Run the garbage disposal

If your dishwasher drains into a garbage disposal, a clogged disposal can back water up into the dishwasher. Run the disposal with cold water for a bit, then try a drain cycle.

If the disposal was just installed, check the knockout plug. New disposals often have a plastic plug in the dishwasher inlet that must be removed during installation. If it was not removed, the dishwasher cannot drain at all. This is a common issue after a new disposal goes in.

Inspect the drain hose and air gap

The drain hose runs from the dishwasher to the sink drain or disposal. Look under the sink for:

• Kinks or sharp bends, especially if items under the sink were recently moved.
• Clogs, which you can sometimes clear by disconnecting the hose and flushing it.
• A proper high loop. Many installations route the hose up high under the counter to prevent dirty sink water from flowing back into the dishwasher.

Check the air gap too. Some homes have an air gap, a small cylinder on the sink or countertop next to the faucet. If water spills out of it or the dishwasher will not drain, the air gap may be clogged. Remove the cover, clean out debris and test again.

Consider the drain pump and check valve

If the filter, disposal, hose and air gap all look clear, the problem may be mechanical.

• The drain pump pushes water out of the dishwasher. If you hear humming but no water moves, or no pump sound at all, the pump may be jammed or failing. Sometimes a small object blocks the impeller.
• The check valve prevents water from flowing back into the tub. If it sticks, water may not drain properly.
• Control issues, such as a failed control board or sensor, can also prevent the drain cycle from running.

These repairs usually call for a qualified technician, especially if they involve electrical components.

Prevent future drainage problems

A few habits go a long way:

1. Scrape large food scraps into the trash before loading.
2. Clean the filter on the schedule your manual recommends.
3. Run the garbage disposal before starting the dishwasher.
4. Use the right detergent and the recommended amount.
5. Run hot water at the sink briefly before starting a cycle.

Does a home warranty cover it?

Many home warranty plans include dishwashers, and a failed drain pump or control board is the kind of mechanical failure they are designed for. Clogs from food debris or foreign objects are a different matter. Some plans exclude them, and the disposal or drain line portion may fall under plumbing stoppage coverage instead. Read your plan's terms before filing a claim.

Our dishwasher coverage page explains what plans typically include, and our pages on garbage disposals and plumbing stoppages cover the related parts.

How Warranty Wizards can help

We help homeowners compare home warranty plans from independent third-party providers and explain how appliances and plumbing stoppages are covered before you buy. You can request a free quote at /get-a-quote/.