Direct answer
For the Whirlpool WDT540HAMZ dishwasher, separate normal sump water from a blocked filter, pump cover, hose, air gap, disposal connection or household drain. First, run Cancel/Drain and listen for the pump.
What this covers
- Whirlpool WDT540HAMZ dishwasher (WDT540HAMZ)
- Whirlpool dishwasher; exact model determines filter, third rack, fan/heat and code display.
- The specific fault this record addresses: will not drain or leaves water in the tub
What it does not cover
- ×The same symptom on a different Whirlpool product line, which has its own record and its own cited source
- ×An on-screen error code whose meaning has not been checked against this exact model's manual
- ×Live electrical, gas, sealed-system, internal battery-cell or structural repair — a technician boundary, not a self-service step
Differential
What actually causes this, and how to tell them apart
These are ordered by how often each one is the answer, not by how easy it is to try. The point of the middle column is that two causes producing the same headline symptom rarely produce the same detail — that detail is what tells you which one you have before you change anything.
- 1
The filter at the base of the tub is clogged
What separates it Water stands in the sump after every cycle, and lifting out the cylindrical filter reveals trapped food, labels, seeds or grease.
How to confirm Most modern dishwashers have a twist-out filter assembly in the tub floor that is intended to be cleaned by the owner regularly. This is the most common cause and the easiest to check.
- 2
A new garbage disposer was installed without removing its knockout plug
What separates it The dishwasher has never drained since a disposer was installed or replaced, and water backs up into the tub.
How to confirm A new disposer ships with a solid knockout plug sealing its dishwasher inlet. It must be driven out before the drain hose is connected, and forgetting it is one of the most common installation faults there is.
- 3
The drain hose has no high loop or the air gap is blocked
What separates it The dishwasher drains but water returns, or the air gap fitting on the sink deck spits water onto the counter.
How to confirm The hose needs either a high loop secured under the counter or a working air gap to stop sink water siphoning back. A blocked air gap is cleared by removing its cap and cover.
- 4
The sink drain or disposer itself is blocked
What separates it The sink also drains slowly or backs up, and running the disposer produces standing water in the sink.
How to confirm This is household plumbing rather than the appliance — the dishwasher is pumping correctly into a line that cannot take it.
- 5
An object is jamming the drain pump impeller
What separates it The pump hums during the drain phase without moving water, or makes a rattling noise. Broken glass, fruit stickers and small bones are typical.
How to confirm With power disconnected and the filter removed, the pump inlet is visible on many models. Anything beyond a visible obstruction is a service repair.
Before you touch a setting
Record this first — changing settings destroys the evidence
Every item below stops existing the moment a reset, re-pair or settings change is made. Written down first, they are what separates the causes above; recovered afterwards, they are guesswork.
- Whether the sink and disposer also drain slowly, which moves this from the appliance to household plumbing.
- Whether a garbage disposer was installed or replaced recently — if so, the knockout plug is the first suspect.
- Whether the pump hums during the drain phase, or is silent.
- When the tub filter was last removed and cleaned.
Twist out the tub filter and clean it thoroughly
ReversibleRinse it under a tap and clear the coarse screen as well as the fine mesh; this is intended as routine owner maintenance.
Confirm the sink and disposer drain normally
ReversibleIf they do not, the problem is household plumbing and the dishwasher is working correctly.
Check the disposer knockout plug if one was recently installed
ReversibleA new disposer ships with its dishwasher inlet sealed, and it must be knocked out before the drain hose is connected.
Clear the air gap, or confirm the drain hose has a secured high loop
ReversibleWithout one of these, sink water siphons back into the tub.
Run a short empty cycle and confirm the sump is dry at the end
ReversibleA small amount of water in the sump is normal on some models; a covered filter is not.
Model-specific
What is true of this model and not of its siblings
Generic advice for the product line fails here. Each item below is a property of this specific model family that changes which of the steps above apply to you.
- Model scope
- WDT540HAMZ. Whirlpool dishwasher; exact model determines filter, third rack, fan/heat and code display.
- Drying — heated dry option
- Has a Heat Dry option (element) for better plastic drying than condensation-only machines; keep plastics off the tub floor. Rinse aid helps.
- Wash & tub
- Stainless tub with adjustable racks and a sensor cycle. A manual filter must be cleaned periodically.
- Drain path
- 'Won't drain' is usually the filter, drain hose, air gap, or an un-removed disposer knockout plug.
- Symptom boundary
- This record covers Whirlpool WDT540HAMZ dishwasher when it will not drain or leaves water in the tub. A different symptom on the same hardware, or this symptom on a different Whirlpool product line, has its own record with its own causes and its own cited source.
Stop boundary
When this stops being a self-service repair
Continuing past any one of these costs more than the repair saves — in safety, in warranty, or in evidence a technician needs.
- !Stop for wastewater backing up into the sink or onto the floor — that is a plumbing blockage and running the dishwasher again will make the mess worse.
- !Broken glass in the filter or sump area means disconnect power and use care; do not sweep it out by hand.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Where the manufacturer's article stops. Whirlpool Product Help publishes this as "Not Draining - Water Remain at End of Cycle - Dishwasher". the maker's article for water left in the tub at the end of a cycle. Probed 2026-08-23: title-verified against a hard-404 control. What that article does not carry is the model boundary — it is written for a product line, and WDT540HAMZ is the scope applied here. Where a control label, terminal, indicator pattern or reset sequence differs on your unit, the manual for that exact model is the authority, not this page and not the article.
Exact questions
Common follow-ups
My Whirlpool WDT540HAMZ smells musty.+
Odour is almost always the filter and trapped food. Pull out and rinse the manual filter at the bottom of the tub, wipe the tub floor and door gasket, and run a hot cycle with a dishwasher cleaner. Scrape plates before loading so less food reaches the filter, and leave the door ajar between uses so the tub dries out. Standing water from a partial drain also causes odour — clean the filter and check the drain if water sits in the tub.
My dishwasher stopped draining right after we got a new garbage disposal.+
The disposer's knockout plug was almost certainly left in. New disposers ship with a solid plug sealing the dishwasher inlet, and it has to be driven out before the drain hose is connected. It is one of the most common installation mistakes there is, and until it is removed the dishwasher has nowhere to pump to.
There's always water sitting in the bottom.+
Start with the filter in the tub floor — most modern dishwashers have a twist-out filter assembly that is meant to be cleaned regularly, and a clogged one is the most common cause of standing water. Note that a small amount of water in the sump is normal on some models; water covering the filter is not.
Does this answer apply to every Whirlpool model?+
No. It is scoped to WDT540HAMZ. Whirlpool dishwasher; exact model determines filter, third rack, fan/heat and code display.
What should I record before troubleshooting not draining or water in bottom?+
Record the complete model identifier, exact message or indicator, software/firmware where visible, the operating stage and what still works.
Why is a factory reset not the first step?+
A reset can erase accounts, networks, maps, schedules or preferences without distinguishing not draining, water in bottom. The ordered checks preserve that evidence.
When should I stop and use qualified service?+
Stop for wastewater backup, broken glass, leaks or water near wiring.
Answer for the exact device and software version shown above.