The waste from an automatic clothes washer must discharge its water through what type of device?

The waste from an automatic clothes washer must discharge its water through an air break or air gap to prevent backflow and contamination of the potable water supply. An air gap is a vertical space between the outlet of the discharge pipe and the water level in the receiving fixture. This design ensures that even if there is a negative pressure or siphoning in the plumbing system, wastewater cannot flow back into the drinking water supply.

By having an air break or gap, it effectively keeps the discharge of the washer’s wastewater separate from other plumbing fixtures, ensuring that any contaminants don’t mix with clean water. This is a critical safety measure in plumbing design to maintain public health standards.

Other devices like a trap, while important for preventing sewer gases from entering the home, do not address the specific need for backflow prevention related to discharging laundry wastewater. A sink can serve as a receiving fixture but does not inherently provide the necessary air gap required for compliance with plumbing codes. A slide valve is not relevant in this context as it pertains to controlling flow rather than preventing backflow.