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Why Do We Need Bottle Traps for Wash Basins?

A bottle trap fitted under a wall-hung basin.

A bottle trap fitted under a wall-hung basin.

The Bottle Trap Below the Basin

Have you ever noticed the bottle trap that sits right under the sink or basin? We all tend to see and choose the most beautiful basins and taps for our bathrooms, but never notice that bottle trap, a basin accessory that does so much more than just make the bathroom look great.

What Is a Bottle Trap and Why Do We Need It?

The bottle trap is an essential element of the basin's plumbing that keeps the bathroom hygienic and odor-free. When we use the basin, the used water goes down the basin waste, into the drainage pipe, and then into the sewer, where a lot of other waste and dirt is accumulating. Naturally, that accumulation involves a lot of nasty and potentially harmful gases. What is there to prevent those foul smells from flowing back up through our drainage pipes, through the wastes, and back into our bathrooms? (Ewww! Sounds bad, doesn't it?) This is what a waste trap (bottle trap, P trap, or U bend) is for.

We need those traps to prevent gases from contaminating bathrooms, thus helping maintain hygiene in the bathroom and keeping it safe for us.

how does a bottle trap work?

how does a bottle trap work?

How Does a Bottle Trap Work?

It is a vessel which has a bigger diameter than the plumbing pipe that comes from the basin. When water gushes down, this vessel fills with the new water. Thus, the trap always remains filled with a certain amount of water.

When the sewer gases waft up the system through the outlet pipes, they reach the bottle trap, but here they find their way sealed with the water that has collected in the trap. The passage remains closed and doesn’t allow the return waste and gases to enter.

Toilet trap

Toilet trap

The Same Basic Concept Works for Other Plumbing Fixtures

You must be wondering if the same thing can happen with the bath tub, shower, and (worst of all) the toilet. Imagine those gases floating out of the toilet and into your bathroom. Good thing the toilet has an inbuilt trap that functions exactly like the bottle trap and prevents sewage gases from returning. The shower and the bath, too, have similar systems.

Choose the Most Suitable Trap for Your Basin

There are various sizes, shapes, and finishes available in any trap style. Choose the most appropriate model to match the finish and design of the other bathroom fittings and sync with the bathroom decor.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.


omolade on January 23, 2020:

very concise and useful

carriethomson (author) from United Kingdom on November 11, 2019:

thank you!

sk sulaman on November 10, 2019:

very good

manatita44 from london on June 26, 2018:

Sweet and concise. I have also learnt something new. Thanks Carrie.

Voltaire on September 07, 2016:

Very useful and thanks for explaining. Was wondering what these things do - many websites just discuss their aesthetics and not their practical use.

Bhavesh solanki on July 18, 2014:

you are very talented girl. keep up the good work.

srinivasan on June 01, 2012:

Very good explanation.

carriethomson (author) from United Kingdom on December 05, 2011:

hey formosan girl! thanks for dropping by! sure do share it with husband! would be very happy if it is useful to him!!


formosangirl from Los Angeles on December 05, 2011:

Interesting. Will be sharing this article with my husband who likes modern bathrooms.

carriethomson (author) from United Kingdom on October 20, 2011:

Hey aceblogs!! thank you so much for the appreciation!! well the details are more than important in any design you see:)) keep visiting


Aceblogs from India on October 20, 2011:

Wow your hubs are so much full of information , frankly speaking i never ever bothered to look at the basin's structure before it , lol . Great share

carriethomson (author) from United Kingdom on September 07, 2011:

hey! katrinasui. thanks for such a wonderful comment!!

katrinasui on September 07, 2011:

carriethomson, you are very talented girl. keep up the good work.

carriethomson (author) from United Kingdom on September 01, 2011:

oh thank you so much prasetio for the appreciation:)


prasetio30 from malang-indonesia on September 01, 2011:

You never cease to amaze me with your talent related with great stuff like this one. Thanks for share with us. Cheers..

carriethomson (author) from United Kingdom on August 30, 2011:

Take Care :)

Joseph De Cross from New York on August 30, 2011:

you are welcome...TC?

carriethomson (author) from United Kingdom on August 30, 2011:

Hi lord!! that was so kind of you, and thanx for liking it and leaving a comment as well :)



carriethomson (author) from United Kingdom on August 30, 2011:

Hi iZeko!! nice name gas trap!! imagine with that name it could be used at such a lot of places ;))

Joseph De Cross from New York on August 30, 2011:

Formidable! just lika a pro..Certainly a real pro! Nice Carrie! VOTED UP.Very useful too!


iZeko on August 30, 2011:

It’s always nice to learn something new. Maybe its name should be changed to gas trap ;-)) Rated up!