The answer to 'why is my sink slow draining' is that a slow-draining sink is usually caused by a clogged drain or buildup of debris in the pipes. Common symptoms include water pooling in the sink and taking a long time to fully drain.
Some common causes of a slow-draining sink include hair, soap scum, food particles, and other debris accumulating in the drain over time. This can restrict water flow and cause the sink to drain slowly. If the clog is severe, it may even lead to a completely stopped-up drain.