Despite the magic it performs in the kitchen, a dishwasher is actually quite simple—it is essentially a watertight box that sprays dishes with hot water and soap, drains out the dirty water, and then dries the dishes.

Hot water is delivered through a supply hose that connects to a valve that controls the water’s distribution to spinning spray arms. A pump gets rid of the dirty water, and an electric heating element dries the dishes. All of this is operated by controls that may be very simple or quite complex.

Problems with proper cleaning usually arise if the water is not hot enough (140 degrees F. is optimal) or if your water is too hard. How hard is your water? Contact your local utility to find out how many grains of hardness your water has. Also, when operating your dishwasher, use the right amount of soap for your water type—1 teaspoon per grain of water hardness.