Which of the following is permitted to discharge to an approved nonpotable water system?

In the context of plumbing systems, a clothes washer is permitted to discharge to an approved nonpotable water system. This is because the discharge from clothes washers typically contains graywater, which is considered nonpotable and can be reused for irrigation or other approved applications, provided that the system is designed and approved for such use.

Clothes washers are often required to have appropriate backflow prevention devices to ensure that nonpotable water does not contaminate potable water. The guidelines around graywater reuse, including the use of water from clothes washers, are designed to promote water conservation and efficient resource use while safeguarding public health by maintaining safe separation from potable water supplies.

In contrast, bidets, floor drains, and sinks typically handle either potable water or wastewater that is not classified as nonpotable and therefore are generally not permitted to discharge directly into a nonpotable water system. Each of these fixtures has specific wastewater disposal requirements to ensure safety and hygiene, making the discharge of their effluents into a nonpotable system inappropriate.