A silent dishwasher has a noise level of 43 decibels or less. That means you can hardly hear the dishwasher. If you have an open kitchen or small apartment, it's useful to opt for a silent built-in dishwasher. This way, you won't hear a buzzing sound in the background when you want to sit on the couch after dinner. A normal dishwasher has a noise level of 44 to 48 decibels.