Adding an Overflow to a Sink
A simple way to re-create the air-release feature in sinks without overflows.
Beautiful vessel sinks made of stone, copper, granite, and marble are very popular in bathroom remodels. Unfortunately, they often drain very slowly because they don’t have built-in overflows. Though not its stated purpose, a secondary benefit of an overflow is to release trapped air when water flows down the drain. I’ve found a simple way to re-create the air-release feature in sinks without overflows. I use a dishwasher tailpiece (in place of the regular tailpiece) and clamp a piece of sturdy vinyl tubing to it. I leave the other end of the vinyl tubing open. It allows air to escape, and water flows rapidly down the drain. For pedestal sinks, you can run the vinyl tubing behind the sink so it’s less obtrusive. And because the work is all done upstream of the trap, there’s no danger of releasing sewer gasses.
— Nick Fera, Brielle, N.J.