Why is there a flexible accordion pipe under the sink?

Sunday, August 19, 2018

Although the flexible, accordion-shaped pipe shown in the photo above is sold in home improvement and hardware stores, it is not approved for installation by plumbing codes, which require that any waste pipe fitting have a smooth interior surface that allows the free flow of drain water and prevents waste buildup clogs.

   Yes, you read that correctly. Although the stuff is allowed to be sold, it is not allowed to be used. The pipe should probably have a label on it like some of the merchandise sold in adult bookstores: “ADULT NOVELTY--NOT FOR ACTUAL USE.” 

   We typically see it used in a sink replacement by a homeowner or handyman that has trouble aligning the drain of the new sink with the U-shaped P-trap below it. A professional plumber can adjust the length of the trap arm (the pipe running from the trap to the wall) or add an angled fitting to turn the trap arm slightly to make everything line up. Also, there is an S-shaped pipe that can used as part of the tailpiece (pipe from the bottom of the sink to the trap) to get everything aligned.

  But the accordion-pipe is a quick and easy fix. Occasionally, we even see it used for a direct connection from the tailpiece to the trap arm, with the old P-trap pipe tossed in the trash. Because the standing water in the trap provides an important safety function of preventing sewer gas from rising up into the home through the sink, this is not a great idea.

    Also, see our blog posts How can I tell what type of plumbing pipe I have? and If all the plumbing drains have water in them and you can still smell sewer gas, what's causing the problem? 

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Here’s links to a collection of our other blog posts about PLUMBING PIPES:

How can I protect my pipes to keep them from bursting during a hard winter freeze in North Florida?

Can galvanized steel pipe still be used for new water lines in a house? 

How can I tell if I have cast iron pipes in my house? 

Why can't a sanitary tee be used for a horizontal-to-horizontal drain pipe connection? 

Is a washing machine drain hose required to be secured at the standpipe?

What are the abandoned pipes sticking out of the wall in my house?  

What are the code requirements for plumbing vent terminations?

What is a dielectric union? 

What's that powdery crust on the pipe connections at the water heater? 

What is the difference between PVC and ABS plumbing pipe?

What is the difference between water service pipe and water supply pipe? 

What are the pipes on my roof? 

What is a P-trap?

Why is old galvanized steel water pipe a problem for homebuyers?

What does polybutylene pipe look like? Why is it a problem? 

• Which water pipes are an insurance problem and possibly uninsurable?

• Can you connect CPVC pipe directly to a gas water heater? 

    Visit our PLUMBING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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