The American Cleaning Institute (ACI)

Dishwasher Basics


Automatic dishwashers represent a tremendous saving in time and effort; they minimize breakage through reduced handling of dishes; they help keep the kitchen neater and more clutter-free; and cleanup after entertaining is simplified. These are benefits that have much appeal to consumers.

In order to ensure that public health standards are maintained, hospitals and many other food service institutions are required by law to clean dishes by automatic dishwashing methods.

The benefits of an automatic dishwasher and the specially formulated detergents and dishwashing products can only be realized if they are used correctly. It is, therefore, important for the user to understand how the dishwasher works, the purpose of its features and how to load and operate it properly. User's manuals and detergent packages contain this information.

 The Dishwasher

The function of the dishwasher is to provide the mechanical action necessary to distribute and direct the detergent solution and rinse waters over, under and around the dishes to loosen and remove soil. The dishwasher must also remove soil-laden waters from the machine after each phase of the cycle and provide for the drying of dishes after the cleaning process has been completed.

Washing Systems

Automatic dishwashers vary in the design of their washing systems (or the means by which water is distributed). Some have a single water source, others may have several water sources. Water is distributed in dishwashers by spray arms or spray towers (or in the case of some older models by an impeller). The design of the spray arms or towers may differ in size, shape and placement in the dishwasher, or in the number, size and location of their water ports (holes through which water is forced). All of the washing systems do a good job, but those with fewer water sources require greater care in loading the dishes to prevent blocking the washing action to various parts of the machine, especially the corners.

The Water

The role of water is to dissolve and carry detergent, wet and loosen soil and effectively rinse the soil away. The velocity with which water is distributed in the dishwasher provides the scrubbing action to loosen and remove soil.


Cleaning in a dishwasher is accomplished with a relatively small volume of water. Contrary to what some people think, the dishwasher does not fill completely as does a clothes washer. The dishwasher, instead, employs several small fills during a cycle to accomplish the washing and rinsing operations. The total volume of water used in a complete cycle can vary from 6 - 10 gallons, depending on the number of washes and rinses included in that particular cycle.

Water pressure in a home may be noticeably reduced at some times because of numerous household water demands. As a result, insufficient water in the dishwasher could occur. This can be avoided by keeping bathing, laundering and other activities requiring quantities of water to a minimum while the machine is in use.


The temperature of the water is an important factor in dissolving detergent, removing food soils and drying dishes properly. To do these things most effectively, the water temperature at the dishwasher should not be lower than 130 degrees F (54.4 degrees C). As temperature is reduced, the removal of greasy and oily soils becomes more difficult; spotting and filming on dishes may occur as well as improper drying.


The amount of hardness minerals and other dissolved solids in water present obstacles