Take it apart and clean it all out. Every few years our kitchen sink/washing machine/second sink waste gets a bit fowled up with hair from washing machine and causes the trap to not work properly. Clean it out with a pipe cleaner and some hot water and she's good another few years.
Take it apart and clean it all out. Every few years our kitchen sink/washing machine/second sink waste gets a bit fowled up with hair from washing machine and causes the trap to not work properly. Clean it out with a pipe cleaner and some hot water and she's good another few years.