The answer to 'why is my faucet slow draining' is that a clogged drain is the most common cause. Over time, hair, soap scum, and mineral buildup can accumulate in the drain pipe, restricting water flow and causing a slow drain. Other potential causes include a blocked aerator on the faucet or a problem with the sink's P-trap.
If your faucet is draining slowly, you'll likely notice water pooling in the sink and taking a long time to empty. The drain may also make gurgling sounds as air is forced through the clogged pipe.