The Most Common Causes of Washing Machine Smell
A smelly washing machine is usually caused by one of three things: mould and mildew in the drum or seal, bacteria and detergent build-up in the drum and pipes, or a blocked pump filter with stagnant water. The good news is that most causes can be addressed without an engineer.
Mould in the Door Seal
The rubber door gasket on front-loading machines is a notorious mould trap. Water and soap residue collect in the folds of the seal, and if the machine is kept closed after use, mould quickly develops. Clean the seal thoroughly with a diluted bleach solution (1 part bleach to 10 parts water) using an old cloth, including deep into the fold. Leave the door ajar after every wash to allow the seal to dry.
Detergent Build-Up in the Drum
Washing at low temperatures (30°C and below) does not kill bacteria or dissolve grease effectively. Over time, a biofilm of bacteria and soap residue builds up inside the drum, producing a musty smell that transfers to laundry. Run a monthly maintenance wash: empty drum, 90°C cycle, with a cup of white vinegar or a proprietary washing machine cleaner. This dissolves build-up and kills bacteria.
Blocked or Dirty Pump Filter
A pump filter clogged with hair, fluff, and debris holds stagnant water, which produces a sulphurous or eggy smell. Clean the filter every 2–3 months as a matter of routine. This also prevents drainage problems before they start.
Soap Drawer Build-Up
Remove the soap drawer completely (press the tab inside the drawer and pull) and soak it in warm water with a little bleach. Clean the housing behind it with a bottle brush. Rinse and replace.
Is an Engineer Needed?
If the smell persists after cleaning the seal, running a hot maintenance wash, and cleaning the filter and drawer, there may be a more serious build-up in the sump hose or a failing seal that is trapping water internally. An engineer can inspect the sump and drainage system. This is a less common cause but worth investigating if self-cleaning does not work.