Herein, does a sink need an overflow?
An overflow is an optional feature found in some bathroom sinks. As the name suggests, it helps prevent the sink from overflowing. An overflow is a small opening in the sink, and it works by letting air flow into the drain while the sink is full of water so the sink drains water more quickly.
Herein, can you use an overflow drain in a sink without overflow?
If the sink you are using the drain with does not have an overflow hole, you will need to purchase a drain without overflow. An overflow is in layman's terms the small hole or slit near the upper part of a sink basin or tub that allows water to drain automatically if the water reaches a certain level.
The overflow drain is a plumbing feature that is added to prevent your sink or bathtub from overflowing with water in case of a clog. For both the bathtub and the sink over you vanity, the overflow operates in the same way. Most bathtubs and sinks are equipped with one of these secondary drains.