Why Is My Dishwasher Not Draining? Causes and Fixes

Opening your dishwasher to find standing water at the bottom is alarming — but in most cases, the cause is straightforward and fixable without a technician. Here's a complete guide to why your dishwasher isn't draining and how to fix it.

1. Clogged Filter (Most Common)

The dishwasher filter catches food particles to prevent them from recirculating or clogging the drain. When it's full, water can't drain properly.

Fix: Locate the filter at the bottom of the dishwasher tub (usually a cylindrical filter you twist and lift out). Remove it, rinse under warm water, and scrub gently with a soft brush. Reinstall firmly. Clean every 1–3 months.

2. Clogged Drain Hose

The drain hose carries water from the dishwasher to the sink drain or garbage disposal. If it's kinked, clogged, or blocked, water backs up in the tub.

Fix: Pull the dishwasher out slightly and inspect the drain hose at the back. Check for kinks and straighten if needed. Disconnect the hose and check for blockages. A drain snake can help clear stubborn clogs. The Flexisnake Drain Weasel Hair Clog Remover Kit (amzn.to/4fBqu8p) is a flexible, easy-to-use tool for clearing drain line blockages.

3. Blocked Garbage Disposal

If your dishwasher drains into a garbage disposal, a clogged or blocked disposal will prevent the dishwasher from draining. This is especially common after the disposal is newly installed — the knockout plug inside the disposal inlet must be removed.

Fix: Run the garbage disposal to clear any blockage. If it's a new installation, check that the knockout plug has been removed from the dishwasher inlet port.

4. Clogged Air Gap

Some installations include an air gap — a small fitting on the countertop or sink that prevents backflow. If it's clogged, the dishwasher won't drain properly.

Fix: Remove the air gap cap (usually just lifts off) and clean out any debris inside. Run the dishwasher again to test.

5. Drain Pump Failure

The drain pump forces water out of the dishwasher. If it's failed or jammed with debris, the dishwasher won't drain at all.

Fix: Check the pump area at the bottom of the tub for debris (glass shards, food chunks, etc.) that may be jamming the impeller. If the pump motor has failed, it will need to be replaced — this is a moderate DIY repair or a job for a technician.

6. Drain Solenoid Failure

On some older dishwashers, a solenoid opens the drain valve. If it fails, the valve stays closed and water can't drain.

Fix: Test the solenoid with a multimeter for continuity. Replace if faulty.

7. Too Much Detergent or Wrong Detergent

Using regular dish soap (not dishwasher detergent) or too much detergent creates excessive suds that can interfere with draining.

Fix: Only use dishwasher-specific detergent. The Finish Powerball Dishwasher Pods (amzn.to/3RE929j) are pre-measured and formulated specifically for dishwashers — no sudsing issues.

8. Drain Check Valve Stuck

The check valve prevents drained water from flowing back into the tub. If it's stuck closed, water can't drain out.

Fix: Locate the check valve (near the drain pump) and inspect for debris or damage. Clean or replace as needed.

Step-by-Step Diagnosis

1. Clean the filter first — this fixes the majority of draining issues
2. Run the garbage disposal if connected
3. Check the drain hose for kinks or blockages
4. Check the air gap if installed
5. Inspect the drain pump area for debris
6. If none of the above work, call a technician

Keep Your Dishwasher Drain Clear

Prevent future draining issues by cleaning the filter monthly and running a cleaning cycle with Affresh Dishwasher Cleaner Tablets (amzn.to/42P5MKQ) to remove grease and buildup from the pump and hoses.