Final answer:
The most likely reason for waste water draining slowly is a clogged drain, which impedes water flow through the pipes. Devices in sink drains are designed to maintain water flow, but clogs can still occur and cause slow drainage.
Step-by-step explanation:
The most likely reason for waste water draining slowly is B. A clogged drain. High water pressure and a recent plumbing inspection are unlikely to cause slow drainage. In contrast, a clog can significantly reduce the flow of water through the pipes, leading to slow draining. A perfect drainage system, on the other hand, would ensure smooth water flow and prevent such issues.
Typically, sink drains have devices designed to maintain an appropriate water flow. These devices may include venting systems to prevent air locks and traps to speed up the flow by maintaining a steady water seal that prevents sewer gases from entering the home. However, a clog, which might be caused by hair, food particles, grease, or other debris, can impede water flow despite these mechanisms.
To maintain a good drainage system, it's crucial to prevent materials that could form a clog from entering the sink and perform regular maintenance. Additionally, understanding aspects like combined sewer systems and devices like sump pumps can help in assessing potential issues impacting drainage.