What’s The Point of a P-Trap?

Underneath the drain of every sink in your home is a device that is critical to the proper functioning of your plumbing, and is playing a major role in keeping the air in your home clean and healthy. If you’ve ever looked inside the cabinet under your sink, you’ve seen it – the humble p-trap. It’s a bent conduit between the horizontal and vertical pipes connecting your sink drain to your plumbing, and it looks like the letter “P” – hence, the name. But what’s the point of this thing?

P-traps have two main purposes, and both are accomplished by a bit of standing water that gets trapped inside the bend. First, this bend thwarts the natural path of gasses that find their way into your plumbing from the septic/sewage system, keeping them from coming up into your home through the drain. Second, the bend can prevent some clogs from happening further down the pipe, since some of what goes down the drain gets trapped in it until it’s flushed out.