The short answer
A smell from a Cove dishwasher is nearly always biofilm in the places water sits between cycles: the filtration, the sump, the gasket channel and the drain hose. Fine filtration collects more material than a coarse screen does, so a machine that is otherwise excellent still needs its filter cleaned by hand on a rhythm.
What you are actually seeing
- A sour or stale smell when the door is opened — Means: on-page
- A drain smell rather than a sour one — Means: on-page
- Visible film around the filtration or the gasket — Means: on-page
- Clean dishes that smell faintly of the machine — Means: on-page
- The smell is worst after the machine has stood unused — Means: on-page
- A burning or hot plastic smell — Means: different-fault — Go to: cove-dishwasher-electrical-safety
- Standing water in the tub with the smell — Means: different-fault — Go to: cove-dishwasher-drainage-failure
- Body: Match what you see before you take anything apart. A sour or stale smell when the door is opened. A drain smell rather than a sour one. Visible film around the filtration or the gasket. Clean dishes that smell faintly of the machine. The smell is worst after the machine has stood unused. Some near-miss symptoms belong on a different page: A burning or hot plastic smell points at an electrical fault to stop using the machine over, covered on cove-dishwasher-electrical-safety; Standing water in the tub with the smell points at a drain fault feeding the smell, covered on cove-dishwasher-drainage-failure.
Causes, ranked for this machine
- Fine filtration and the sump holding food debris between cycles — Why this rank: First because premium filtration catches more material than a coarse screen, and none of it clears itself
- Biofilm in the door gasket channel — Why this rank: The channel stays wet and is almost never cleaned
- A drain hose or air gap holding stale water — Why this rank: Explains a drain smell rather than a sour one, and it is a different reservoir with a different fix
- Running only short or eco programmes, so the machine never reaches a temperature that clears the film — Why this rank: A habit rather than a fault, and correcting it prevents the smell returning
- A dry trap or a plumbing smell from the sink rather than the machine — Why this rank: Last because it is not the appliance, but it is worth ruling out before anything else is considered
- Body: Ranked for a premium built-in dishwasher: hard-plumbed, on a dedicated supply, installed under a worktop by a fitter, quiet by design, with hand-cleaned filtration and a condensation dry that depends on rinse aid. Most likely: Fine filtration and the sump holding food debris between cycles. First because premium filtration catches more material than a coarse screen, and none of it clears itself. Next most likely: Biofilm in the door gasket channel. The channel stays wet and is almost never cleaned. Third: A drain hose or air gap holding stale water. Explains a drain smell rather than a sour one, and it is a different reservoir with a different fix. Fourth: Running only short or eco programmes, so the machine never reaches a temperature that clears the film. A habit rather than a fault, and correcting it prevents the smell returning. Fifth: A dry trap or a plumbing smell from the sink rather than the machine. Last because it is not the appliance, but it is worth ruling out before anything else is considered.
What to check, in order
- Remove and clean the whole filter assembly and look at what comes out
- Wipe the gasket channel and the door edge and look at the cloth
- Run a hot cycle with a dishwasher cleaner and an empty machine
- Judge whether the smell is sour or drain-like, because the reservoir differs
- Body: Each check rules out the causes above it. First, remove and clean the whole filter assembly and look at what comes out. Second, wipe the gasket channel and the door edge and look at the cloth. Third, run a hot cycle with a dishwasher cleaner and an empty machine. Fourth, judge whether the smell is sour or drain-like, because the reservoir differs.
Checks you can safely make yourself
- Switch off at the breaker, remove the full filter assembly, wash it in hot water with a brush and clear the sump beneath it — Tools: brush, gloves — Time estimate: half an hour
- Wipe the gasket channel and the door edge with a cloth and a mild detergent, working right into the fold — Tools: cloth, detergent — Time estimate: a quarter of an hour
- Run the hottest cycle with a proprietary dishwasher cleaner and nothing in the machine — Tools: dishwasher cleaner — Time estimate: one long cycle
- Lift the air gap cover on the worktop, where one is fitted, and clear any debris from the chamber — Tools: none — Time estimate: a quarter of an hour
- Run a hot programme rather than an eco cycle once a week for a month and judge whether the smell returns — Tools: none — Time estimate: a month of habit
- Body: Checks an owner can make with the machine switched off at the breaker, or by watching a cycle. Step one: Switch off at the breaker, remove the full filter assembly, wash it in hot water with a brush and clear the sump beneath it. Tools: brush, gloves. Time: half an hour. Step two: Wipe the gasket channel and the door edge with a cloth and a mild detergent, working right into the fold. Tools: cloth, detergent. Time: a quarter of an hour. Step three: Run the hottest cycle with a proprietary dishwasher cleaner and nothing in the machine. Tools: dishwasher cleaner. Time: one long cycle. Step four: Lift the air gap cover on the worktop, where one is fitted, and clear any debris from the chamber. Tools: none. Time: a quarter of an hour. Step five: Run a hot programme rather than an eco cycle once a week for a month and judge whether the smell returns. Tools: none. Time: a month of habit.
Safety first
Safety
Switch off at the breaker before removing filtration or reaching into the sump, and wear gloves against broken glass. Never mix a chlorine cleaner with any other cleaning product inside the machine. Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. unplug-before-service
Where the owner fix ends
Call a technician when the filtration and sump are clean, the gasket channel has been washed, a hot cleaner cycle has run, the air gap is clear and a drain smell still returns. That points at the drain hose interior or the sink plumbing, beyond an owner clean.
Nearest pages of the same kind
Generalized information
This page is generalized across the Cove dishwasher line. Fully integrated machines carrying a custom cabinet panel and machines with a finished front share the ranking above but not every part, and this page does not cover a specific model, control revision or installation. Family- and model-specific pages, where they exist, are linked below.
Links: - [Common COVE Dishwasher Problems](/blog/cove-dishwasher-problems) - [COVE Dishwasher: Abnormal Noise or Vibration](/blog/cove-dishwasher-abnormal-noise) - [COVE Dishwasher: Does Not Clean or Dry](/blog/cove-dishwasher-cleaning-performance) - [COVE Dishwasher: Controls, Display or Error Code](/blog/cove-dishwasher-control-fault)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
