We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
DIY

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What is a P-Trap?

Deanna Baranyi
By
Updated: May 16, 2024
Views: 182,561
Share

Almost any household equipment that drains water has a p-trap. Sinks, bathtubs, washing machines, all have p-traps to drain the waste water. A p-trap is comprised of a tailpiece, the curved trap piece, and a drain elbow. The drain elbow for a p-trap fits into the drain pipe which goes directly into the wall.

Codes require a p-trap (or an s-trap) any place there is an open drain line that flows into the drain-waste-vent system. As the name implies, the drain-waste-vent system removes solid, liquid or gas waste from the home through drains and vents. For example, as the water empties from a sink, it goes through the p-trap, on to the drain line, and ends up in the sewage system.

The important thing about the p-trap is that it is has a water seal along the curve of the trap. The seal prevents noxious air or gases to backflow from the sewer line, but the original waste can still exit into the sewage system. If the gases were allowed back into the home, not only would they smell, but they could cause illnesses and have even been known to explode.

A p-trap can be made of metal or of plastic. Although metal is usually considered to be more durable, the reality is that the plastic will last longer. Although the metal traps may look nicer, they quickly corrode. One squeeze at the bend, even with fingers, and if it gives in – even slightly – it needs to be replaced. There is one exception to this rule: heavy-gauge brass traps will last a very long time.

Depending on where the trap is located, it may vary in size. Bathroom traps are 1.25 inches (3.2 cm) in diameter. Kitchen traps are 1.5 inches (3.8 cm) in diameter.

Every time the drain is used, water is flushed through the trap and fresh water replaces the old water. Solids will begin to stick to the trap over the course of time; consequently, clogs will occur. In those cases, it is probably time to replace the trap. A beginner can replace the p-trap in about an hour; however, an expert can do the same job in about twenty minutes. In some cases, a trap that has a cleanout plug can be cleaned out without removing and installing a new trap – simply rinse the water through the plug and remove the debris with an auger or other tool.

It is important to know the specific plumbing codes for a particular country before removing or installing a new p-trap. For example, in the United States, white plastic PVC, polyvinyl-chloride, pipe is commonly used for drains. But, in Canada, black ABS, acrylonitrile butadiene styrene, is used. Every country is different, so the proper research is necessary before delving into any plumbing project.

Share
HomeQuestionsAnswered is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Deanna Baranyi
By Deanna Baranyi
Deanna Baranyi, a freelance writer and editor with a passion for the written word, brings a diverse skill set to her work. With degrees in relevant fields and a keen ability to understand and connect with target audiences, she crafts compelling copy, articles, and content that inform and engage readers.
Discussion Comments
By anon346391 — On Aug 28, 2013

Not mentioned here is that S-traps are now generally forbidden by most plumbing codes in U.S.

By anon303059 — On Nov 13, 2012

What does a p trap look like in comparison to an s trap? Sorry, I don't know about plumbing.

By Snoopy123 — On Jun 01, 2010

My husband works for a municipal wastewater department, so professional advice coming through! A P-trap is a section of plumbing located underneath most drains in your home. These U-shaped pipes remain full of water at all times to prevent horrible odors from escaping into your home from the main sewer line. In addition to preventing those pesky roaches from becoming houseguests, it also serves as an emergency jewelry catcher.

Very important! Remember to maintain your trap with a plumber 'snake' to clean the grime that can coat your plumbing. That grime can also cause stinky situations and water to build up into your sink.

Pixiedust, I hope your P-traps stay grime and stinky free!

By pixiedust — On Nov 06, 2009

I stayed at a hotel once where every time I flushed the toilet a horrible smell, similar to the smell of an outhouse, would fill the room. Turns out the ptrap wasn't working properly. That's when I learned that it's the pee trap we have to thank for nice- or at least neutral-smelling bathrooms.

Deanna Baranyi
Deanna Baranyi
Deanna Baranyi, a freelance writer and editor with a passion for the written word, brings a diverse skill set to her...
Learn more
Share
https://www.homequestionsanswered.com/what-is-a-p-trap.htm
Copy this link
HomeQuestionsAnswered, in your inbox

Our latest articles, guides, and more, delivered daily.

HomeQuestionsAnswered, in your inbox

Our latest articles, guides, and more, delivered daily.