Which of the following is NOT a required plumbing device?

The correct choice indicates that a laundry tub is not a required plumbing device in residential construction according to many building codes. While sinks, toilets, and showers are essential fixtures that are typically mandated for the functionality and sanitation of a dwelling, a laundry tub is not universally required. Building codes focus on essential plumbing fixtures that satisfy the basic needs for hygiene, sanitation, and daily living activities.

Sinks are necessary for food preparation and personal hygiene. Toilets are critical for sanitation and waste disposal, and showers provide essential facilities for personal hygiene. The laundry tub, while beneficial for washing clothes and other items, is considered an auxiliary plumbing fixture, and its inclusion is generally left to the preference of the homeowner or builder. Local building regulations may offer guidelines, but they typically do not classify the laundry tub as a necessary plumbing device in the same way that other fixtures are mandated.