• 12 parts
  • Checked September 2026

Parts of a Faucet

A single-handle faucet pulled apart, and an older compression valve cut open.

Parts of a Faucet

Name Date

Tap any part to read, rename or leave it out

1 2 3 4 5 6 7 8 9 10 11 12
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Write the name of each numbered part.Answer key

  1. Handle
  2. Cartridge
  3. O-ring
  4. Body
  5. Spout
  6. Aerator
  7. Base gasket
  8. Mounting nut
  9. Supply lines
  10. Stem
  11. Washer
  12. Valve seat

Drawn for this site on 2026-10-05 by script, from our own geometry laid out from the usual sizes of the hardware: a single-lever faucet lifted apart along its axis and seen a little from above, and a compression valve cut through its middle with the cut metal hatched. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: the sink and its drain

All 12 parts on the diagram

Show the list

Start here: 7 main parts 6

  1. Handle Turns the cartridge to set the flow and the temperature.
  2. Cartridge The valve that controls on and off, flow and hot-cold mixing. A worn one is a common cause of drips.
  3. Body Holds the cartridge and the water channels, where hot and cold mix.
  4. Spout Carries water from body to basin.
  5. Aerator Mixes air into the stream for a softer flow with less splashing. Unscrew it to clean it.
  6. Mounting nut Screws up the shank under the sink to hold the faucet down.

Single-handle faucet 3

  1. O-ring Small rubber seals that stop water leaking past moving parts.
  2. Base gasket A rubber seal between the faucet and the sink deck. It keeps water from getting underneath.
  3. Supply lines Hoses carrying hot and cold water up from the shut-off valves.

Compression valve 3

  1. Stem Screws down when the handle turns, pressing the washer onto the seat.
  2. Washer A rubber disc that seals against the seat to stop the water.
  3. Valve seat The ring the washer presses on. When worn or pitted, the faucet drips.

How this list was compiled: Read 2026-09-26. (1) A faucet maker's guide, https://landonbath.net/parts-of-a-faucet-complete-guide-to-faucet-components/ : handle, spout, aerator at the tip, escutcheon plate, cartridge (a worn one a common cause of leaks), valve stem, O-rings, washer and valve seat in compression faucets, retaining clip or nut; mounting nuts, rubber gaskets, threaded shanks, hot and cold supply lines, shut-off valves. (2) This Old House, The anatomy of a kitchen faucet, https://www.thisoldhouse.com/kitchens/the-anatomy-of-a-kitchen-faucet : aerator mixes air into the stream and removes for cleaning; spout delivers water from the body; handle controls the valve; cartridge and ceramic disc valves; the body is where hot water and cold mix; the O-ring in the faucet base; supply lines. (3) A second faucet maker's guide, https://atorneira.com/understanding-faucet-structure-a-practical-guide/ : body, cartridge or valve core, handle, spout, aerator, supply hoses, gaskets and O-rings, mounting hardware; rubber washer and spindle in older faucets. (4) Wikipedia, Tap (valve), https://en.wikipedia.org/wiki/Tap_(valve) : aerators; older taps close a rubber washer onto a valve seat, both subject to wear. Licence: own work

The drawing: Drawn for this site on 2026-10-05 by script, from our own geometry laid out from the usual sizes of the hardware: a single-lever faucet lifted apart along its axis and seen a little from above, and a compression valve cut through its middle with the cut metal hatched. Nothing is traced or copied. The forms were checked by eye against a photograph of a single-lever tap (Benreis, 2015, CC BY 3.0) and a cut-away picture of a tap (Chabacano, 2007, CC BY 2.0) on Wikimedia Commons; both were looked at only. Licence: own work

How it works

These are the parts of a faucet as a plumber names them: a modern single-handle faucet pulled apart, then an older compression valve cut open. The same parts are in a bathroom or a kitchen faucet.

Read the full guide

A cartridge faucet

Lift the handle off and you reach the cartridge, the valve that sets the flow and mixes hot and cold. O-rings seal round it. The body holds it, the spout carries the water, and the aerator at the tip softens the stream.

Under the sink

A gasket seals the faucet to the sink. Underneath, a mounting nut on the threaded shank holds it down, and two supply lines bring hot and cold water up from the shut-off valves.

  • In an older compression faucet the stem screws a rubber washer down onto the valve seat. A drip usually means a worn washer or a pitted seat.

Questions and answers

What is the part at the end of a faucet called?

The aerator. It screws onto the tip of the spout and mixes air into the water for a smoother stream with less splashing. Unscrew it to clean out grit and scale.

What part of a faucet usually causes a leak?

In a modern faucet, a worn cartridge or its O-rings. In an older compression faucet, a worn washer or a damaged valve seat. Turn off the supply valves before taking either apart.

What holds a faucet to the sink?

A mounting nut under the sink, screwed up the faucet's threaded shank. A gasket between the faucet and the sink seals the joint.

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