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Why Does My Bathroom Sink Drain Have a Big Bend In It?

If you’ve ever looked under your bathroom sink, you’ve probably noticed a strange “hairpin” bend in your pipes. It seems odd and even counter-productive, but with most bathroom plumbing systems, it’s pretty much the standard. So why does your bathroom sink drain have a big bend in it instead of going directly to the wall? The answer can tell you a lot about the nature of modern plumbing.

The bend is commonly known as a U bend, and it’s appeared in plumbing since the late 18th century. The modern version was perfected by a British plumber with the unfortunate name of Thomas Crapper. (Yes, really.) It actually serves as a kind of vent. The shape collects water from your sink, which creates a seal between your bathroom and the larger sewer system beyond. That keeps sewer gases from creeping up the pipes and making your bathroom smell.

That function depends on a proper seal in the bend, and similar factors in your plumbing can affect it as well. Most plumbing codes require a specific length between the bend and the closest outside vent. This keeps atmospheric pressure from affecting the bend’s function and ensures that it does its job.

Because of its shape, U bends can also fall prey to clogs and blockages very easily. Toothpaste, hair gel, beard clippings and similar parts of our daily grooming rituals can become lodged in the pipe, often requiring professional plumbing services to clean out. It’s not always ideal, but when the alternative is a bathroom full of sewer gas, it seems like a small price to pay. You can help prevent such clogs by carefully monitoring what you dispose of in your bathroom sink.

When the time comes to clean out your U bend, or if the seal breaks and you find yourself beset by unpleasant odors, give The Sunny Plumber a call. Our trained Scottsdale bathroom plumbing experts cover most of the greater Phoenix area, including Scottsdale. Bathroom plumbing is a significant cornerstone of our business, and we have the experience and know-how to handle any issues you may come across. If you know why your bathroom sink drain has a big bend in it, you can anticipate some of the problems that we’re here to solve. Give us a call today!

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