Rhode Island Journeyman Plumber Practice Exam

Through what does waste from an automatic clothes washer discharge?

1. Drain Pipe

2. Air Gap

3. Septic Tank

4. Backflow Preventer

The correct answer is: Air Gap

The waste from an automatic clothes washer primarily discharges through an air gap. An air gap is a crucial plumbing mechanism that prevents the backflow of wastewater into clean supply lines, thus ensuring the potable water system remains safe and free from contamination. It operates by allowing a physical separation between the discharge line of the washer and the drainage point, significantly reducing the risk of siphoning used water back into the washer or the water supply. While drain pipes are involved in the overall plumbing system and are responsible for carrying wastewater away, they do not inherently provide the protection against backflow that an air gap does. Septic tanks collect and treat wastewater from various sources, including washers, but they are not the direct conduit for discharge. Similarly, a backflow preventer is a device specifically designed to stop backflow in a plumbing system but is not the means through which the washer discharges its wastewater. Therefore, the dependence on an air gap for safe discharge of the waste is paramount when considering the plumbing involved with automatic clothes washers.