NOCTI Plumbing Practice Test

To operate correctly, a residential dishwasher should be supplied with which type of water line?

Potable hot water line Cold water line Tempered water line Waste line

Correct Answer:

Potable hot water line

Explanation:

Dishwashers clean most effectively when they start with hot, potable water. Hot water helps detergents work better, loosens grease quickly, and supports better sanitizing and drying. Supplying a hot, safe (potable) water line means the unit doesn’t have to heat a large amount of cold water, saving energy and ensuring the wash reaches the right temperatures quickly. A cold water supply would force the dishwasher to heat more water internally, increasing cycle time and energy use, and some models rely on a hot supply to meet their designed operating temperatures. The waste line is for draining used water, not supplying fresh water, and a tempered line wouldn’t provide the necessary temperatures for proper cleaning.

Access more questions from this quiz

Continue to NOCTI Plumbing Practice Test for more practice questions and the full quiz experience.

Access More Questions