Have you ever heard of a p-trap? While the name may conjure up all sorts of different definitions, we can clear up any confusion by explaining how it works. Essentially, it’s a specifically designed bend between the horizontal and vertical piping under a sink drain or at the base of a toilet that looks like the shape of the letter P. Now that you’ve read that, you’re probably remembering that you’ve seen something like this a million times in your life.

But what does this thing do? Well, inside the deepest part of the bend lies a little bit of standing water. This water, along with the bend, helps to prevent sewer gas from traveling up into your home through the drain. It also gathers a small amount of debris from the water as it travels through the bend, helping to prevent clogs. These two effects are why it’s called a trap.