Which aspect of a plumbing system helps prevent moisture accumulation in walls and ceilings?

The venting system plays a crucial role in maintaining the overall health of a plumbing system by preventing moisture accumulation within walls and ceilings. It allows air to enter the drainage system, which helps to create an equilibrium in pressure. This equalization is important because, without proper venting, negative pressure can occur when water flows through the pipes, potentially leading to siphoning in traps. If traps are siphoned dry, sewer gases can enter the building, and improper drainage can result in water backing up or stagnating, which in turn can lead to moisture accumulation and mold growth within building materials.

In contrast, the drainage system is responsible for the removal of wastewater from the property, while the supply system delivers fresh water to fixtures. Neither of these systems directly addresses issues related to airflow and moisture control in the structural components of the building. A backup system typically refers to an emergency mechanism in case of a failure, which does not play a direct role in moisture management. Thus, the venting system is the key component that helps mitigate moisture issues by ensuring that the plumbing system operates efficiently.