The short answer
A smell from a Costway compact dishwasher is nearly always stale water sitting in the filter, the base or the drain hose between uses. These machines are often used a few times a week and then left closed, which is exactly what a small wet tub needs to develop a smell. Cleaning and airing it out is the whole fix.
What you are actually seeing
- A sour or stale smell when the door is opened — Means: on-page
- A smell that is worst after the machine has stood unused — Means: on-page
- Visible film around the filter or the gasket — Means: on-page
- Clean dishes that smell faintly of the machine — Means: on-page
- A drain smell coming from the hose rather than the tub — Means: on-page
- A burning or hot plastic smell — Means: different-fault — Go to: costway-dishwasher-electrical-safety
- Standing water with the smell — Means: different-fault — Go to: costway-dishwasher-drainage-failure
- Body: Match what you see before you take anything apart. A sour or stale smell when the door is opened. A smell that is worst after the machine has stood unused. Visible film around the filter or the gasket. Clean dishes that smell faintly of the machine. A drain smell coming from the hose rather than the tub. 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 costway-dishwasher-electrical-safety; Standing water with the smell points at a drain fault feeding the smell, covered on costway-dishwasher-drainage-failure.
Causes, ranked for this machine
- Water left standing in the filter and the base between uses — Why this rank: First because a compact machine used a few times a week is wet and closed for days at a time, which is exactly how a smell develops
- Biofilm in the door gasket channel — Why this rank: The channel stays wet and is almost never cleaned
- Stale water in the drain hose, which lies coiled between uses — Why this rank: This machine's drain hose is stored rather than plumbed, so it holds its own puddle
- Running only short, cool cycles that never clear the film — Why this rank: A habit rather than a fault, and correcting it prevents the smell returning
- A smell from the sink drain rather than the machine — Why this rank: Last because it is not the appliance, but it is worth ruling out before any parts
- Body: Ranked for a countertop or portable dishwasher that connects to the kitchen tap with a quick-connect adapter or fills from an internal tank, and drains through a hose into the sink. Most likely: Water left standing in the filter and the base between uses. First because a compact machine used a few times a week is wet and closed for days at a time, which is exactly how a smell develops. Next most likely: Biofilm in the door gasket channel. The channel stays wet and is almost never cleaned. Third: Stale water in the drain hose, which lies coiled between uses. This machine's drain hose is stored rather than plumbed, so it holds its own puddle. Fourth: Running only short, cool cycles that never clear the film. A habit rather than a fault, and correcting it prevents the smell returning. Fifth: A smell from the sink drain rather than the machine. Last because it is not the appliance, but it is worth ruling out before any parts.
What to check, in order
- Remove and clean the filter and look at what comes out
- Wipe the gasket channel and the door edge
- Drain and dry the hose, and store it draining rather than coiled
- Run a hot cycle with a dishwasher cleaner and an empty machine
- Body: Each check rules out the causes above it. First, remove and clean the filter and look at what comes out. Second, wipe the gasket channel and the door edge. Third, drain and dry the hose, and store it draining rather than coiled. Fourth, run a hot cycle with a dishwasher cleaner and an empty machine.
Checks you can safely make yourself
- Unplug the machine, lift out the filter, wash it in hot water with a brush and clear the base beneath it — Tools: brush, gloves — Time estimate: a quarter of an hour
- Wipe the gasket channel and the door edge with a cloth and a mild detergent, working into the fold — Tools: cloth, detergent — Time estimate: a quarter of an hour
- Hold the drain hose over the sink so it empties completely, then store it hanging rather than coiled on the worktop — Tools: none — Time estimate: a few minutes
- Run the hottest cycle with a proprietary dishwasher cleaner and nothing in the machine — Tools: dishwasher cleaner — Time estimate: one long cycle
- Leave the door ajar between uses for a week and judge whether the smell returns — Tools: none — Time estimate: a week of habit
- Body: Checks an owner can make with the machine unplugged or by watching a short cycle. Step one: Unplug the machine, lift out the filter, wash it in hot water with a brush and clear the base beneath it. Tools: brush, gloves. Time: a quarter of an hour. Step two: Wipe the gasket channel and the door edge with a cloth and a mild detergent, working into the fold. Tools: cloth, detergent. Time: a quarter of an hour. Step three: Hold the drain hose over the sink so it empties completely, then store it hanging rather than coiled on the worktop. Tools: none. Time: a few minutes. Step four: Run the hottest cycle with a proprietary dishwasher cleaner and nothing in the machine. Tools: dishwasher cleaner. Time: one long cycle. Step five: Leave the door ajar between uses for a week and judge whether the smell returns. Tools: none. Time: a week of habit.
Safety first
Safety
Unplug the machine before removing the filter, and wear gloves against broken glass. Never mix a chlorine cleaner with another cleaning product inside the machine, and keep the kitchen ventilated while cleaning. 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, or claim under warranty, when the filter and base are clean, the gasket has been washed, the hose is emptied, a hot cleaner cycle has run and the door is left ajar, and the smell still returns. That points inside the machine, beyond an owner clean.
Nearest pages of the same kind
Generalized information
This page is generalized across the Costway dishwasher line. Countertop machines with an internal tank, countertop machines on a tap adapter and rolling portable machines share the ranking above but not every part, and this page does not cover a specific model or control revision. Family- and model-specific pages, where they exist, are linked below.
Links: - [Common COSTWAY Dishwasher Problems](/blog/costway-dishwasher-problems) - [COSTWAY Dishwasher: Abnormal Noise or Vibration](/blog/costway-dishwasher-abnormal-noise) - [COSTWAY Dishwasher: Does Not Clean or Dry](/blog/costway-dishwasher-cleaning-performance) - [COSTWAY Dishwasher: Controls, Display or Error Code](/blog/costway-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.
