Maytag Dishwasher Not Draining — Fix It Fast

Common Symptoms

• Water pooling at the bottom of the tub after the cycle ends
• Cycle runs but stops before completing with standing water remaining
• Error code indicating a drain fault (F8 E1 or similar on Maytag MDB models)
• Humming sound during drain portion of the cycle with no water movement
• Odor from the dishwasher between uses

Most Likely Causes

1. 1

   Kinked or Incorrectly Routed Drain Hose — Most Common

   The dishwasher drain hose must form a high loop — rising to the underside of the countertop before descending to the drain connection. Without this high loop, water in the drain can siphon back into the tub between cycles. A kinked hose anywhere along its run also prevents drainage entirely. Inspect the full hose length from the dishwasher pump outlet to the drain connection under the sink.

2. 2

   Disposal Knockout Plug Not Removed

   When a new garbage disposal is installed, a knockout plug seals the dishwasher drain port inside the disposal. If the dishwasher drain hose is connected to the disposal and the knockout plug was never removed, no water can drain. Use a flathead screwdriver and hammer to knock out the plug from inside the disposal inlet, then retrieve the plug piece from inside the disposal drum.

3. 3

   Clogged Filter and Sump

   The MDB-series twist-lock filter and the sump cavity beneath it accumulate food debris, grease, and broken glass. A severely clogged sump restricts water from reaching the drain pump inlet, reducing drain flow to a trickle. Regular monthly filter cleaning prevents this. Remove the filter assembly and clean the sump cavity thoroughly before testing any electrical components.

4. 4

   Failed Drain Pump WPW10348269

   The drain pump motor impeller forces water through the drain hose at the end of each cycle. The pump motor can fail electrically (open winding) or mechanically (broken impeller or jammed debris). A failed pump often makes a loud humming sound during the drain phase as the motor attempts to run but produces no flow. Test the pump motor windings with a multimeter — expect 5–15 ohms across the motor terminals; an open reading indicates a failed motor.

5. 5

   Failed Check Valve WP8269227

   The check valve is a small flapper or ball valve at the drain pump outlet that prevents drained water from flowing back into the tub. A check valve that is stuck closed blocks drainage entirely; one stuck open allows drain water to re-enter the tub after the pump stops. Inspect the valve flapper for cracks, debris lodged under the seat, or distortion that prevents it from opening fully.

6. 6

   Door Latch Signal Preventing Drain Completion

   If the dishwasher door is opened mid-cycle and not fully re-latched, the control board may interrupt the active cycle — including the drain phase — leaving water in the tub. The control board requires a continuous door-latch signal to complete each cycle phase. If the door latch switch is intermittently failing, the board may abort drain cycles randomly. Test the latch switch continuity with the door closed.

Quick DIY Checks

1. 1Open the cabinet under the sink and trace the dishwasher drain hose. Verify it forms a high loop — rising to the underside of the countertop and secured with a clip or zip tie before dropping down to the drain connection. Straighten any kinks in the hose. If the hose connects directly to the garbage disposal, confirm the disposal knockout plug has been removed (look for a plastic cap inside the disposal drain inlet port).
2. 2Remove the lower rack and twist out the MDB-series filter assembly counterclockwise. Lift out both the cylindrical fine-mesh filter and the flat coarse-filter basket. Rinse both thoroughly under warm running water and scrub with a soft brush. Remove any standing water from the sump cavity with a sponge or turkey baster, then inspect the sump opening for debris (broken glass, seeds, food scraps) blocking the pump inlet screen.
3. 3With the filter removed, shine a flashlight down into the sump. Locate the drain pump inlet port and confirm it is clear. Run a short rinse cycle — listen for the drain pump activating (a medium-pitched hum or whir, approximately 5–10 seconds at cycle end). No sound at all suggests the pump motor or its wiring is faulty; humming without flow suggests a jammed impeller or blocked outlet.

Repair vs Replace

Recommended Tools & Parts

• Drain Pump and Motor Assembly

  Complete drain pump and motor assembly for Maytag MDB-series dishwashers. Replaces failed pump motor or broken impeller.

  $55–$90

  Buy on Amazon →

• Check Valve

  Drain check valve / flapper valve that prevents backflow into the tub. Located at the drain pump outlet.

  $8–$18

  Buy on Amazon →

• Door Latch Assembly

  Door latch and switch assembly — also used in not-starting diagnosis. Controls cycle continuation signal to the control board.

  $20–$40

  Buy on Amazon →

Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.

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