Standing Water in the Bottom of a Monogram Dishwasher: What Causes It

You open the door expecting dry, warm dishes and find a shallow pool in the bottom. A small amount of water is sometimes visible in the sump after a normal cycle, but standing water that sits above the filter or smells stale is not normal. The dishwasher is either not draining or not draining fully.

What the water is telling you

During a cycle, water is pumped out through a drain hose to the sink drain or a disposer. If any part of that route is blocked, closed, or kinked, water stays behind. Where it stays gives a hint. Water that drains slowly and leaves a thin film behind often points to a partly blocked filter. Water that never moves at all points toward the pump, the hose, or the sink connection.

If the dishwasher shows a code, write it down. Monogram dishwashers have entries for water that does not empty out, such as the flashing rinse light covered on our page about the flashing rinse light on a Monogram dishwasher, and another for a dishwasher that keeps draining, covered under the flashing temp light.

Start with the filter and the tub floor

The filter at the bottom of the tub catches food, labels, and bits of glass. If it is clogged, water backs up. With the dishwasher off and the power switched off at the breaker, remove the filter assembly according to your manual, rinse it under running water, and look for debris around it. Check the floor of the tub for a broken piece of glass, a toothpick, or a fruit pit. Do not reach into the drain area with bare hands if you suspect sharp debris. Replace the filter fully and firmly.

Check the sink side

Run the kitchen sink and see whether it drains normally. If the sink drains slowly or gurgles, the dishwasher cannot empty into it. If a disposer is connected, the dishwasher hose connects to the disposer inlet, and that inlet may have a knockout plug that was never removed during installation, or a build-up of food. Run the disposer clear while the dishwasher is off.

Look at the drain hose under the sink. It usually loops high before dropping to the drain connection, and that loop keeps sink water from running back into the dishwasher. Look for a kink, a squashed section, or a hose that sags into a trap. In older buildings and condos, the sink plumbing is often shared or has long runs, so a slow drain at the sink is worth mentioning to the building manager or a plumber.

Air gap and check valves

Some installations include an air gap on the countertop or sink deck. If the air gap is clogged with debris, drainage slows. Lift the cap and clear the opening, from the outside only. A technician checks the drain hose, check valve, and pump if the water persists.

When the pump or controls are the cause

If the filter, the hose, and the sink check out, the cause is inside the dishwasher. A technician looks at:

• The drain pump and its impeller, which can jam on broken glass or debris.
• The drain valve or check valve, which controls water flow.
• A partial blockage in the sump or the hose running from it.
• The control board and any sensing that tells the dishwasher to drain.
• A float or switch that misreads the water level.

The diagnosis confirms which of these is at fault before anything is replaced. We give you a written estimate, and no repair begins without your approval.

Safe checks in order

1. Switch off the breaker, then remove and rinse the filter assembly.
2. Look for visible debris in the tub floor.
3. Run the kitchen sink and the disposer to confirm the sink side is clear.
4. Check the visible drain hose for kinks, and the air gap if there is one.
5. Write down any light pattern or beep you saw.
6. Restore power and run a short rinse, and note whether the water moves out.

What not to do

Do not pour drain cleaner into the tub, because the chemicals sit on the parts and can damage seals and plastic. Do not remove the lower access panel or the kick plate to reach the pump. Do not run the dishwasher repeatedly while it is full of water. Do not bail water while the power is on.

If the dishwasher leaks onto the floor, shut off the water supply and the breaker, and see our leak detected page.

Installation details that matter

A built-in dishwasher sits under the counter with its hoses tucked into a narrow cavity. After a remodel or a countertop change, a hose can be bent sharply or pinched by the cabinet. Panel-ready dishwashers have a front that hides the controls, and a code may only be visible when the door is open. The model number is usually on the door edge or inside the tub, and our post on finding your Monogram model number shows where to look.

A model such as the ZDT800SSYSS, a current 24-inch unit, shares the same basic drain design as other Monogram dishwashers, but pump and valve parts depend on the exact number.

When to book

Book when the filter and sink are clear and the water still stands, when the dishwasher hums but does not drain, or when a code returns. Our Monogram dishwasher repair page explains the visit, and the Monogram dishwashers guide covers the lineup. If the cycle also stops before finishing, our post on a Monogram dishwasher that stops mid-cycle is worth reading.

Frequently asked questions