How to Fix a Dishwasher That Won't Drain: Filter, Pump, and Hose (2026)

Frequently Asked Questions

Where is the dishwasher filter and how do I clean it?

The filter is located at the bottom center or rear of the dishwasher tub, under the spray arm. Most modern dishwashers (made after ~2010) have a two-part filter: a cylindrical fine mesh filter that lifts straight up or twists counterclockwise to remove, and a flat coarse filter beneath it. Remove both parts and rinse under running water. Use a soft brush to clean the mesh — avoid anything abrasive that could damage the screen. Reinstall by inserting the flat filter first, then twisting the cylinder clockwise until it clicks. A clogged filter is the most common reason for standing water and also causes poor wash performance.

How do I check and clear a clogged dishwasher drain hose?

The drain hose runs from the drain pump outlet (underneath the dishwasher) to either the garbage disposal inlet or a dedicated drain stub on the sink drain. To check: (1) Pull the dishwasher forward enough to see behind it (unplug first and turn off the water). (2) Inspect the hose visually for kinks — especially where it bends around the cabinet frame. A single 180-degree kink completely stops drainage. (3) The drain hose should loop up high under the countertop before going down to the disposal or drain — this high loop (or an air gap if installed) prevents backflow from the sink into the dishwasher. If the loop has dropped, drainage slows or stops. (4) To clear a clog: disconnect the hose at both ends (have a towel ready), blow through it to check for blockage, and run water through it. Food debris, broken glass, and grease can partially or fully block the hose. Replace the hose if it is cracked or the inside is heavily coated ($10–$20 for a replacement hose).

What is the garbage disposal knockout plug and how does it cause draining problems?

When a dishwasher drain hose is connected to a garbage disposal, it connects to a dedicated inlet on the side of the disposal body. New garbage disposals ship with a plastic knockout plug installed in this inlet — it is designed to be punched out before connecting the dishwasher hose. If someone replaced the disposal and did not remove the knockout plug, the dishwasher drain is completely blocked. To check: disconnect the dishwasher drain hose from the disposal inlet. Look inside the inlet — you should see a clear opening into the disposal. If you see a solid white or black plastic disk, that is the knockout plug. Use a screwdriver and hammer to punch it into the disposal cavity, then retrieve the plug pieces through the disposal opening before they damage the grinding blades.

How do I test and replace the drain pump?

The drain pump is a small motor and impeller assembly that forces water out through the drain hose. It is located under the dishwasher beneath the tub. Signs of a failed drain pump: (1) You hear the dishwasher cycle through but no draining noise occurs, or (2) you hear a humming sound during the drain cycle but water does not move. To access the drain pump: unplug the dishwasher, remove the lower kick panel, and tip the dishwasher back slightly or lay it on its side (protect the door). The drain pump is usually the smaller of the two motors visible (the main wash pump is larger). Disconnect the electrical connector and the drain hose from the pump outlet. Twist or unclip the pump to remove it. Test the pump motor with a multimeter for continuity across the terminals — a burned-out motor shows no continuity. Replacement pumps are $30–$70 and model-specific. Installation is the reverse of removal.

Why does my dishwasher drain slowly but not completely?

Slow but incomplete draining usually indicates a partial blockage rather than a complete failure. The most common causes in order of likelihood: (1) Partially clogged filter — the filter is catching debris but not completely blocked. Clean it thoroughly. (2) Partial drain hose kink — the hose is bent enough to restrict flow but not stop it entirely. Straighten the hose routing. (3) Partially blocked air gap — if your sink has a chrome dome on the countertop near the faucet (the air gap), unscrew the cap and check for debris inside. Air gaps clog with grease and food particles. Clean the air gap with a bottle brush. (4) Drain hose connected too far into the standpipe or disposal — the hose end should not go more than 8 inches into the drain connection or it can create a siphon effect. (5) Grease buildup inside the drain hose — run a cycle with a cup of white vinegar and then a cup of baking soda to help dissolve grease buildup.

How do I prevent dishwasher drain problems in the future?

Preventive maintenance significantly reduces dishwasher drain failures: (1) Clean the filter monthly — or every 2 weeks if you run the dishwasher daily or do not pre-rinse dishes heavily. Most filters are designed for easy cleaning without tools. (2) Run the garbage disposal before starting the dishwasher — if the drain hose connects to the disposal, a full disposal trap backs up into the dishwasher drain path. (3) Scrape plates before loading — large food debris bypasses the filter and collects in the drain pump area. (4) Run a dishwasher cleaning cycle monthly (use a commercial dishwasher cleaner tablet or a cup of white vinegar on the bottom rack) to dissolve grease. (5) Inspect the drain hose high loop annually — vibration and movement over time can allow the loop to drop, enabling backflow and slow drainage.

Dishwasher won’t drain: (1) Clean the filter — the most common cause by far. Most modern dishwashers have a removable cylindrical filter in the tub floor that must be cleaned monthly.

Standing water in the bottom of your dishwasher after a cycle is almost always fixable in under an hour with no special tools.

What You Need

• Dishwasher drain pump replacement — the most common parts repair; order by your model number
• Dishwasher drain hose — replace if kinked, cracked, or older than 10 years
• Multimeter — for testing drain pump motor continuity
• Dishwasher cleaner tablets — monthly use prevents grease buildup in drain components
• Bottle brush set — for cleaning the filter mesh and drain hose interior
• Hose clamp assortment — if the drain hose connection clamps are corroded or stripped

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Step 1: Clean the Filter (Start Here)

The filter is the most overlooked component in dishwasher maintenance and the most common cause of draining problems.

Open the dishwasher and remove the lower spray arm (usually lifts straight off or unscrews counterclockwise). Beneath it you will see the filter assembly — a cylindrical fine mesh filter surrounded by or sitting above a flat coarse filter.

To remove: twist the cylinder counterclockwise about a quarter turn and lift straight up. Remove the flat filter beneath it.

Rinse both filters under warm running water. Use a soft-bristle brush to scrub the mesh screens. If there is significant grease buildup, soak the filters in warm soapy water for 10 minutes.

Reinstall by placing the flat filter first, then inserting the cylindrical filter and twisting clockwise until it locks.

Run a short cycle and check if the dishwasher drains.

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Step 2: Check the Drain Hose Routing

Pull the dishwasher out from its cabinet space to see the drain hose. Unplug the dishwasher before pulling it forward.

Inspect the entire length of the drain hose from where it exits the dishwasher to where it connects to the garbage disposal or sink drain. Look for:

• Any kink or sharp bend in the hose
• The high loop — the hose should rise up behind the cabinet before coming back down to the drain connection. If the loop has sagged or if no loop exists, water can back-siphon from the sink into the dishwasher, and drainage slows.

Straighten any kinks and re-secure the high loop by attaching the hose to the underside of the countertop with a cable clip or zip tie.

If the hose is corrugated or shows cracks, replace it. A replacement hose costs $10–$20 and the swap takes about 20 minutes.

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Step 3: Check the Garbage Disposal Inlet

If the drain hose connects to a garbage disposal and you recently installed a new disposal, the knockout plug may still be in place.

Disconnect the drain hose from the disposal inlet (spring clamp or hose clamp). Look inside the disposal inlet port — you should see a clear opening. If you see a solid plastic disk, use a flat screwdriver and hammer to knock it into the disposal cavity, then reach in and retrieve the plug before operating the disposal.

If the disposal is old, run it for 30 seconds before reconnecting the dishwasher drain hose. A full disposal trap backs up through the dishwasher drain path and prevents proper draining.

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Step 4: Test the Air Gap (If Installed)

Some installations use an air gap — a small chrome cylinder mounted on the countertop or sink rim next to the faucet. It has two hose connections underneath the sink.

If your installation has an air gap and draining is sluggish:

1. Unscrew the decorative chrome cap.
2. Remove the plastic cover underneath.
3. Clear any debris from inside the air gap body with a bottle brush.
4. Rinse with water and reassemble.

Air gaps clog with grease and small food particles over time. A clogged air gap allows the dishwasher to partially drain but water backs up because the downstream hose to the disposal cannot pass water fast enough.

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Step 5: Test the Drain Pump

If cleaning the filter and correcting the drain hose does not resolve the problem, the drain pump has likely failed.

Identifying the pump:

1. Unplug the dishwasher.
2. Remove the lower kick panel.
3. Tilt or lay the dishwasher on its side to access the bottom (remove the bottom door hinge screws and protect the door).
4. The drain pump is the smaller motor assembly visible on the underside of the tub, connected to the drain hose outlet.

Testing the pump:

Disconnect the electrical connector from the pump and use a multimeter set to continuity or resistance. Test across the two motor terminals — a functioning motor shows continuity. No continuity indicates a burned-out motor that requires replacement.

Also check the pump impeller: with the pump disconnected, rotate the impeller by hand through the pump inlet. It should spin freely. A jammed impeller (often caused by broken glass or bone fragments) can also cause drain failure without burning out the motor.

Replacing the pump:

Order a replacement drain pump by your dishwasher model number — typically $30–$70. Installation reverses the removal steps. Always replace the pump gasket or O-ring if included with the replacement part to prevent leaks.

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Step 6: Check the Drain Solenoid (Older Dishwashers)

Some older dishwashers (pre-2005) use a separate drain solenoid valve rather than a dedicated drain pump. If your older dishwasher does not drain, locate the solenoid on the main pump assembly. It is a small cylinder with two electrical terminals.

Test with a multimeter for resistance — a good solenoid reads approximately 40–80 ohms. A failed solenoid reads open (OL). Replacement solenoids are $15–$30.

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When to Call a Professional

• The drain pump tests good and the hose is clear, but the dishwasher still does not drain (possible control board issue)
• You find standing water under the dishwasher indicating a pump seal failure
• The repair cost approaches the cost of dishwasher replacement (especially on units over 10 years old)

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Related Reading

• How to Fix a Dishwasher That Won’t Fill — inlet valve, float switch, and water supply diagnosis
• How to Fix a Garbage Disposal — clearing jams and resetting the disposal that shares the drain
• Annual Home Maintenance Schedule — monthly filter cleaning and other appliance maintenance tasks