Bathroom Guide

Replaced plumbing under bathroom sink and have a question regarding the u-shaped pipe.?

My son replaced my vanity yesterday and had to replace all the pipes as the pipes were deteriorated. We took the old pipes to the hardware store and they duplicated the set up. However, when he added the faucet, the design was 1-1/2" approx. to short to reach the drain pipe in the wall. It appears the new faucet mechanisms were not as long as the orig. faucet. He was able to change the set up by eliminating the U-shaped piece of the pipe. I was told by someone today that there "must" be that piece as part of the assembly. This was his first attempt with plumbing and I wanted to make certain what he did was not going to cause problems down the road. He basically has the faucet piece connected to a double slip coupling connecting that to a long piece of pipe leading to another double slip coupling with a pipe leading into the drain line. By adding the coupling on the faucet setup and removing the U-shaped pipe it fit. I am noticing I can hear the drain when the toilet flushes!

Public Comments

1. that u shape piece of pipe is called a p trap it is there to prevent sewer gases from entering your house yes you need it
2. Yes you need the U shaped pipe, if you(he) were to cut the faucet pipe down, would it then configure with the rest of the pipes arranged correctly under the sink? The faucet pipe comes at a fixed length, you can take a hack saw and cut it down to make it fit. Sorry I don't know the names of all the terms, but I work on my plumbing myself.
3. Yeah you need that “U” shaped pipe it’s the trap that holds water to keep the sewer gas out. They have flexible fittings in your situation. They look like the flexible part on a straw. Any hardware store should be able to help you.
4. This U shaped piece is referred to as a 'P' trap. although this part is not "necessary", I would highly recommend finding a way to attach it. Function of a P-trap: the p trap literally traps water in the bend of the pipe blocking smells and sounds within the drains. if this is left off nasty smells will start to arise out of the drain. this is also the reason you can hear sounds when you flush the toilet.
5. The u shaped drain pipe under the sink serves a purpose. The water that collects in the u serves as a barrier for the methane gas that forms in the sewer lines. Without it you can be poisoned from the methane gas. Do not change the set up under sinks.
6. Yes, the U-shaped pipe is called a "trap" and is absolutely essential because, without it, toxic raw sewer gas will enter your home. It is easy to splice in extra plastic pipe. Just go back to the store, get a foot or two of pipe and a couple of couplings and some abs adhesive. Keep working at it. Most plumbing jobs take an amateur few tries to get right.
7. Call a plumber. I just had a +$300,000.00 home destroyed this weekend because a $3.50 stop cock was not installed properly on a vanity. It is not worth the risk to your home and family to not have this installation checked out by a professional. That "U" shaped pipe is the single most important piece of plumbing in your entire house!