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The U-Shaped Pipe Under Your Sink: What It's Really For

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Serving Washington D.C., Montgomery & Frederick Counties


Serving Washington D.C., Montgomery & Frederick Counties



The U-Shaped Pipe Under Your Sink: What It’s Really For

How often have you thought about the shape of the plumbing under your sink, such as that unusual U-shaped bend in the drainpipe before it enters the wall? Perhaps only a few times, such as when you open the cabinets under a bathroom or kitchen sink to retrieve cleaners or a roll of paper towels. That U-shaped pipe is one of those parts of a house’s plumbing that performs an important task, but which you don’t need to pay attention to…until something goes wrong with it.

Whatever your woes with your plumbing, you can count on the skill and expertise of Tuckers Air Conditioning, Heating & Plumbing to solve it. We’ll send a plumber in Gaithersburg, MD to your home and have your plumbing restored quickly. Give us a call today to schedule an appointment.

That U-shape is called the P-trap

You may think of the bend in the pipe under the sink as a “U,” put plumbers call it a P-trap. (Tilt your head and look at it from the side, and then you’ll see the “P” shape.) This simple construction placed into a drainpipe is a clever way to prevent sewage gas from the decomposing wastewater farther down the pipe from escaping up through your drains and into your home. Gravity traps an amount of water inside the bend after it goes down the drain, and this liquid plug serves as a block against sewer gas.

A common reason that people begin to detect sewer odors in their homes is because of dried P-traps. If a sink doesn’t receive frequent use—such as one in a guest bathroom—the water in the P-trap will evaporate, allowing sewer gas to escape up the drain. To fix this, run water down the sink for a few minutes to restore the plug.

P-traps can become problems for your drains as well: they will start to accumulate hair, soap scum, and grease, fat, and oil, over time, and this may eventually cause a sink clog. Sometimes a plunger will clear this, but thicker organic clogs will require the help of a plumber with a mechanical drain snake or hydro-jetting equipment. In some cases, a plumber must detach the P-trap from the drainpipe to clean it.

Take good care of the P-trap: avoid pouring liquid grease, oil, or fat down your drains, and place drain caps over bathroom and shower sinks to prevent too much hair and soap scum from getting through. If clogs do occur, never hesitate to contact a professional plumber in Gaithersburg, MD to clear up the trouble. (But don’t reach for the liquid drain cleaners! They are toxic and acidic.) Call up Tuckers Air Conditioning, Heating & Plumbing to have a professional plumbing service provide you with all the help your home plumbing needs.

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