If you've tried do-it-yourself solutions like using a plunger or drain snake and the clog persists, or if you see any of the following symptoms, you should call a plumber right away:
Water that drains slowly: If the water in your sink or shower is draining more slowly than usual, there may be a clog that requires professional cleaning.
foul odors: A buildup of waste materials may be the cause of persistently foul odors coming from your drain.
Gurgling sounds: If you hear gurgling coming from your drain or notice bubbles appearing in the shower or sink, there may be an obstruction blocking the airflow.