A small amount of clean water below the filter can be normal. Most dishwashers retain water in the sump to keep pump seals from drying out. Water that covers the bottom of the tub, reaches the door, or smells bad is not normal. A blockage or failed drain pump is usually the cause.

Do not order a part based on the symptom alone. Check the simple items first. Then use the dishwasher model number to identify the correct OEM replacement part if a component has failed.

Know What Water Is Normal

Look under the lower rack. A shallow pool in the lowest sump area may remain after a completed cycle. You may not see it until you remove the filter.

Standing water across the visible tub floor is different. The dishwasher should remove this water during the drain portion of the cycle. Food particles, broken glass, labels, or a failed drain pump can stop that process. Dirty water can also return to the tub after the dishwasher drains.

Run a Cancel or Drain cycle before you inspect the machine. Listen for the drain pump. A steady hum with little or no water movement often points to a failed drain pump. No sound can point to a pump, wiring, door switch, or electronic control issue.

Why a Dishwasher Leaves Water in the Tub

The water valve is stuck open or leaking.

If the dishwasher drains completely, but has clean water in the bottom after a few hours - your valve may be leaking.  Check for moisture below the inlet.  

A clogged filter or sump blocks water flow

Many dishwashers have a removable filter assembly at the bottom of the tub. When grease, food residue, paper labels, or small objects collect in this area, water cannot flow to the drain pump.

Remove the filter and rinse it with warm water. Clean the filter screen and the sump area beneath it. Use a soft brush if needed. Do not force sharp tools into the pump inlet. A piece of glass or a bone fragment can damage the impeller or cut your hand.

Run a short cycle after cleaning the filter. If the dishwasher drains normally, no replacement part is needed. Clean the filter on a regular schedule, especially if dishes go into the machine with heavy food residue.

The drain hose is kinked, clogged, or installed incorrectly

The drain hose carries water from the dishwasher to the sink drain, garbage disposal, or air gap. A kink behind the dishwasher can slow or stop drainage. Grease buildup inside an older hose can do the same.

Pull the dishwasher out only if you can do so without pulling on the water line or power cord. Inspect the hose for crushing and sharp bends. Check the connection under the sink as well. Remove the hose and clear it if you find a blockage.

The hose must also have a high loop, unless local code requires an air gap. The high loop fastens the hose high inside the sink cabinet before it drops to the drain connection. This prevents sink water from flowing back into the dishwasher. Keep in mind, that if you haven't changed the hose routing by replacing the hose, disposal, sink connection, etc....the high loop probably isn't the problem.

The garbage disposal inlet is blocked

This problem often occurs right after a disposal replacement. It does not usually require dishwasher parts.

A new garbage disposal has a knockout plug in the dishwasher drain inlet. The installer must remove this plug before the dishwasher can drain into the disposal. If the plug remains in place, the dishwasher may hum during drain but the water has nowhere to go.

Disconnect power before checking the disposal. Remove the dishwasher drain hose from the disposal inlet and inspect the port. If the plug is still inside, remove it according to the disposal instructions. Make sure the hose clamp is secure when you reconnect the hose.

The drain pump is blocked or has failed

The drain pump uses an impeller to push water through the drain hose. A small object can jam the impeller. The motor can also wear out, and the pump housing or seal can leak.

Signs of a drain pump problem include a humming sound without drainage, a grinding sound, intermittent draining, or no pump sound during a drain command. Some models give a drain-related error code. Check the technical sheet or use and care guide for the code meaning before you replace parts.

Turn off power at the circuit breaker before you access the pump. Depending on the model, the pump may be reached from inside the tub or from below the dishwasher. Check the pump inlet for debris first. If the impeller is clear but the pump does not run or cannot move water, replace the drain pump with the OEM part specified for the model number.

A check valve lets drain water return

Some dishwashers use a check valve, drain flapper, or backflow device near the pump outlet. This part lets water leave the dishwasher but limits reverse flow. If it sticks open, water from the hose, sink drain, or disposal can move back into the tub.

Backflow is more likely when the dishwasher is immediately empty after a cycle but has water in it after a few minutes. Inspect the drain hose routing before you replace a check valve. A correctly installed high loop may solve the problem. If routing is correct and the valve is damaged or does not close, install the correct replacement.

The air gap or sink drain is restricted

An air gap is the small fitting often mounted near the kitchen faucet. It protects the dishwasher from drain backflow. If water spills from the air gap during a cycle, clean the cap and internal passages. Also check the hose that runs from the air gap to the disposal or sink drain.

A slow kitchen sink can cause dishwasher drainage problems too. The dishwasher may be working correctly, but the sink drain cannot accept the discharge water fast enough. Clear the sink drain restriction before you service the dishwasher.

The electronic control or wiring does not start the drain pump

The control board sends power to the drain pump at the end of the wash and rinse sections. A loose connector, damaged wire, failed door switch, or defective control can prevent the pump from receiving power.

This is less common than a clogged filter or hose. It needs a careful diagnosis. With power disconnected, inspect the pump connector and harness for corrosion, heat damage, or broken wires. A technician can use a meter to verify whether the control sends the correct voltage during a drain command. Replace a control board only after you rule out the pump, hose, and wiring.

Diagnostic steps

Start with the checks that cost nothing and require the least disassembly. This order can prevent an unnecessary pump or control board purchase:

1. Run Cancel or Drain and listen for the pump
2. Is the water clean?  Drain and let sit overnight.  If it fills, replace the valve.
3. Clean the filter and remove debris from the sump area.
4. Check the drain hose, high loop, air gap, and sink drain.
5. Inspect the disposal inlet and remove its knockout plug if it is still installed.
6. Check the drain pump and its wiring after disconnecting power.

If the dishwasher drains during Cancel but leaves dirty water after a normal cycle, also check how you load dishes. Large pans or tall utensils can block the lower spray arm. Poor washing can leave food debris that later blocks the filter, even though the drain system itself works.

Choose Parts by Model Number, Not Appearance

Drain pumps, check valves, filter assemblies, and control boards can look similar across brands. The mounting tabs, wire connectors, impeller design, and electrical ratings can differ. A part that looks right may not fit or operate correctly.

Find the model number on the dishwasher frame, usually along the inner edge of the door. Record the full number, including revision characters. Use that number to match the exact OEM component. Virginia Service Supply stocks genuine replacement parts for major dishwasher brands, which helps you match the repair to the appliance rather than rely on a universal substitute.

Before you reinstall any hose or pump, check each clamp, gasket, and connector. Run a short cycle and inspect below the dishwasher for leaks.