Know The Jargon So You Don’t Pay For Something You Don’t Need!

What in the world is a P-trap? How about a S-trap? Or a U-bend? No, these are not terms related to some heretofore undiscovered Greek lexicon, they are simple terms related to plumbing that you should probably know if you are doing or having done any work on the plumbing in your home. For example, the P-trap is a horizontal pipe that passes into the waste pipe leading away from the sink or toilet. It is usually at the P-trap that most clogs occur because of the sharp angle. The S-trap is the connected vertical portion leading further down into the drain, again located both on sink and toilet drains.

Usually on a toilet drain the lumen of the S-trap becomes slightly larger than then P-trap to avoid blockages. The U-bend is a “U” shaped piece of pipe usually located directly before the P-trap. Its purpose is to maintain a small pool of water sitting in the pipe which prevents any backflow of air from lower in the drain pipe. Drain pipes can be notoriously odorous, so this U-bend full of water provides a wonderful service in preventing odors from regurgitating into the home from the drain pipe below.

As opposed to these terms, a riser is a pipe that carries water into the home rather than into a drain system away from the home. It is part of the supply line, not the drain line. These are important differences to know when discussing any plumbing issues with a professional.