There are several reasons why your bathroom sink may become clogged. Some of the most common causes include:
Hair
Over time, hair can accumulate in your pipes and cause a blockage.
Soap Scum
Soap scum can build up in your pipes over time and cause a clog.
Toothpaste
Toothpaste can also accumulate in your pipes and cause a blockage.
Foreign Objects
Items such as jewelry, cotton swabs, and other small items can accidentally fall down the sink and cause a clog or a drain backup.