What is the primary function of a plumbing drainage system?

• A. To collect and store water for future use.
• B. To convey wastewater away from the building safely.
• C. To distribute clean water throughout the building.
• D. To filter contaminants from sewage.

Answer: (B)

The primary function of a plumbing drainage system is to convey wastewater away from the building safely. This involves transporting waste fluids from sinks, toilets, showers, and other plumbing fixtures to a treatment facility or a septic system, effectively removing harmful substances and preventing the contamination of living areas. A well-designed drainage system is crucial for maintaining sanitation and hygiene in residential buildings, as it helps to prevent issues such as backflow, sewer gas infiltration, and blockages that can lead to health hazards.

Other options relate to aspects of plumbing but do not accurately capture the main purpose of a drainage system. For example, collecting and storing water pertains more to plumbing supply systems, while distributing clean water focuses on delivering potable water throughout a structure. Filtering contaminants from sewage is a function associated with wastewater treatment processes rather than a direct role of the drainage system itself. Thus, the correct answer highlights the essential role of the drainage system in ensuring a safe and effective disposal of wastewater.