An overflow drain is a secondary drainage hole (or series of holes) located near the top rim of a sink basin, just below the counter level. It connects internally to the main drain pipe, preventing water from spilling over the edge if the sink is left running with the stopper closed or drain clogged.
The overflow hole connects to a hidden channel that runs behind the sink basin. This channel bypasses the main bowl and connects directly to the tailpiece of the drain assembly, just below the sink flange. overflow drain sink
When water rises above the primary drain but below the sink rim, it enters the overflow channel (built into the sink’s porcelain or metal) and flows down to join the main drain pipe. This creates an air gap that also helps the sink drain faster by allowing air into the drain system, preventing airlock. An overflow drain is a secondary drainage hole
October 26, 2023 Subject: The Engineering and Maintenance of Bathroom Sink Overflow Drains This channel bypasses the main bowl and connects