After hosting a dinner party and saying goodbye to your guests, you will find yourself facing a mountain of dirty dishes. Your dishwasher could be the key to getting to bed before midnight but not if a foul smell rolls out of it when you open it up. You can fix the most common causes of dishwasher odour and prevent the smells from returning.
Normally, all you should smell inside your dishwasher is the lingering scent of your dishwashing detergent when you unload clean dishes from your machine. On occasion you might smell something else when you open up the door. Smells that signal a problem inside your dishwasher include the foul scent of bacteria and rotting food and the pungent odour of sewer gas. You will not notice these odours when your dishwasher door is closed or when it is running. Instead the smells will invade your kitchen when you open the dishwasher door to place a dirty glass inside it.
The cause of the odour of bacteria is food particles building up in the bottom of the dishwasher, which occurs when the unit fails to wash away food waste from dishes. The food waste attracts bacteria, which feeds on the food waste and causes it to spoil. The problem becomes worse when the dishwasher does not heat water to a sufficiently high temperature to kill off bacteria during wash cycles, so the bacteria levels rise. The odour of a sewer is caused when sewer gas drifts up through the kitchen drainpipe and into your dishwasher.
To get rid of the smell of bacteria, you must remove the food particles on which the bacteria are feeding. Empty the dishwasher of all dishes, and gather together a large wad of paper towels. There could be broken glass from damaged dishes and glasses in the bottom of your dishwasher, so work carefully. Wipe away all built-up food and grease from the bottom of the dishwasher, and dispose of the paper towels. Sewer gas enters your home when there is a problem with the trap in the drainpipe that should be sealing the gas down in the sewer, which is a potentially serious health risk; contact a plumbing professional for help.
You can prevent bad odours from returning to your dishwasher by maintaining it. Once a month, pour a cup of white vinegar into the dishwasher's detergent dispenser and run the unit while empty. You can also use a half cup of bleach, which will clear food particles and kill bacteria before they have a chance to build up and become a problem. If you do not run your dishwasher often, sprinkle baking powder in the bottom of it between loads, which will help control odour and keep the unit smelling fresh.