The Ins and Outs of Bathroom Sink Plumbing

Although you use your bathroom sink numerous times a day, you’ve probably never thought too much about its plumbing. Understanding the parts of under sink plumbing, however, may make your daily life a lot easier. Grasping bathroom sink plumbing and how it works may help you keep all sorts of time-consuming and costly problems at bay. The advantages of learning about under the sink plumbing parts are truly plentiful. If you ever need to purchase a specific plumbing piece, being aware of part names can often simplify matters greatly.

An In-Depth Plumbing Under Bathroom Sink Guide for You

Bathroom sinks are equipped with numerous straightforward components that can experience obstructions, leak or even just break. These parts tend to be simple to locate and purchase. If you’re able to identify these parts, though, it may make your shopping experience even more hassle-free and efficient.

Shutoff Valves

Shutoff valves or “stop valves” refer to tiny valves that are situated in the middle of supply hoses and incoming water supply pipes. Supply hoses are essentially tubes that attach to sink faucet tailpieces. Although shutoff valves generally are made out of metal, they’re occasionally made out of plastic, instead. The majority of these valves have handles that are oval in shape. You can rotate these handles in order to shut and open the valves.

know your sink plumbingShutoff valves enable people to shut off water supplies for sinks exclusively. They make it so that people do not have to turn off the water supplies for their entire living spaces. These valves are accessible in sets of two. The first valve takes charge of cold water. The second valve is at the helm of hot water. Shutoff valves in many cases rely on compression fittings. This frees people of soldering duties during the installation process. If you tackle shutoff valve replacement, you have to switch off your entire home water supply first.

Supply Tubes

Look at your shutoff valves and sink faucet tailpieces. You may notice a couple of slender supply tubes near them. These tubes are typically made out of chromed copper, gray plastic, white plastic mesh or braided wire mesh. Supply tubes tend to be joined to shutoff valves and tailpieces using nuts. Since these tubes occasionally experience breakdowns, having to swap them out is in no sense out of the ordinary.

Drain Pipe

Your sink drain pipe is part of the extensive plumbing system for your residence. It attaches to trap arms using a slip-nut joint. Bathroom sink drainpipes generally have three-inch diameters, but exceptions are possible. Understanding piping under bathroom sink matters can help people recognize all sorts of potential issues including clogging and reduced water pressure.


Your P-trap consists of two distinct components. These are the aforementioned trap arm and the U-bend. They’re a couple of twisted pipe sections that enable the sewer line and the sink to link up. It’s a straightforward safety device that safeguards standing water and because of that stops gases from sewers from emerging and exiting sink drains. The lower sections of U-bends stay brimming with water. This is to stop gases from accessing it.

When water moves through drains, existing bend water is promptly cleared out. Fresh water then takes its place. P-trap components are put together using slip-nut joints. Homes that were constructed rather long ago, however, may have solvent-glue traps.

Drain Tailpiece

This tailpiece is a straight pipe component that joins to the sink drain fitting’s lower section. Sinks that have pop-up drains have drain lever rod setups that attach directly to ports that are behind the tailpieces. These tailpieces generally depend on slip nuts to connect to drain fittings. These are rings that are threaded. People can make them looser or tighter manually. Channel-type pliers can do the trick, too. If you look below the nut, you’ll spot a plastic washer that contributes to a seal that’s watertight.

Other Bathroom Sink Plumbing Parts to Know

Dependable bathroom sinks tend to remain sturdy and functional for roughly 15 years or so. Understanding all of the specific components that make them what they are may help you keep things working efficiently for as long as possible.

  • sink plumbingThe actuator arm is the supply tube that attaches itself to the faucet valve.
  • The elbow is the arched fitting that has two sides with female connections.
  • The spout is a tube that rises above the appliance as a means of promoting the flow of water.
  • The cover is a pipe that hides plumbing elements in order to contribute to a pleasant and streamlined visual arrangement.
  • The washer is a slender plate that has a shape that’s reminiscent of a disk. It has an opening that splits up threaded fastener loads.
  • The lock nut is a nut that sits securely inside of designated pipe sections. People screw them onto different pipes for purposes of connecting them both together.
  • The lift or the connecting rod is a faucet element that handles pop-up drain opening duties. It does this any time lift rods go down for the purpose of safeguarding water.
  • The gasket is a device that’s both even and flat. It consists of rubber or fiber and paves the way for a watertight seal in the middle of metal joints.
  • The ferrule is a metal piece that conceals lavatory overflow openings.
  • The escutcheon is the shield or the flange that’s right under the handle of the faucet. It conceals the hole and the faucet stem alike.
  • The angle stop is the water supply shutoff valve that adjusts the specific direction in which supply water travels.
  • The waste arm or the waste pipe is a drain extension pipe that pushes sink drains out toward walls.
  • Pop-up or trip level drains are significant remote control waste components.
  • The pop-up stopper, last but definitely not least, is the component that safeguards drains. It promotes drain flow as well. It does away with clogs that are associated with the introduction and presence of foreign objects.


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