What does 'drainage' entail in a piping system?

Drainage in a piping system refers specifically to the removal of wastewater or stormwater from a building. This process is crucial for sanitary reasons and ensures that water can flow away from structures to prevent flooding and water damage.

In a typical drainage system, gravity is often utilized to transport waste from various plumbing fixtures through a network of pipes to an appropriate disposal point, such as a municipal sewer system or a septic system. The effectiveness of this system directly impacts a building's hygiene and safety, minimizing the risk of clogs or backflow.

The other options involve different concepts that are not the primary function of drainage. Filtering water pertains more to treatment processes rather than the removal of waste. Storing wastewater for reuse relates to water recycling systems, which is separate from the drainage function. Mixing different types of waste does not accurately define drainage and can complicate waste management. Therefore, the focus of drainage is solely on the removal aspect, making it a critical component in plumbing systems.