Kitchen Sink Parts Explained with Simple Diagrams

You’re standing under the sink with a wrench, staring at a confusing maze of pipes, trying to figure out which part is leaking—and you realize that understanding what each piece does is the first step to fixing it yourself.

TL;DR

A kitchen sink has three main systems: the water supply (faucet and supply lines), the sink basin (bowl, drain, strainer), and the drainage system (tailpiece, P-trap, and wall pipe). The faucet delivers hot and cold water, the strainer catches food debris, the garbage disposal grinds waste, and the P-trap prevents sewer gases from entering your home. Understanding these parts helps you troubleshoot clogs, leaks, and other common sink issues without calling a plumber every time.

The Big Picture: How It All Works Together

Think of your kitchen sink as two systems working in harmony. The water supply system brings fresh water in through the faucet. The drainage system sends used water and food waste out through the pipes.

When you turn on the faucet, water flows from your home’s supply lines (one hot, one cold) through the faucet and into the sink basin. When you release the drain stopper, water travels down through the strainer, through the tailpiece, and into the P-trap, where it’s held briefly before flowing into your home’s main drain line. The P-trap’s curved shape always holds a little water, creating a seal that prevents sewer gases from coming back up through your drain.

Visible Parts: What You See Above the Counter

1. Sink Basin

The basin is the bowl that holds water. It’s the most visible part of your sink and comes in various materials—stainless steel (most common), porcelain, ceramic, granite composite, and cast iron. Single-bowl sinks give you one large space for washing big pots, while double-bowl sinks let you multitask (soak on one side, rinse on the other).

2. Faucet

The faucet controls water flow and temperature. Most modern faucets are single-handle designs that mix hot and cold water with one lever, while traditional models have separate handles for hot and cold. Key faucet parts include:

• Spout: The curved tube where water exits
• Aerator: The small mesh screen at the tip that mixes air into the water—reduces splashing and saves water
• Controls: The handles or levers that adjust temperature and flow

3. Spray Head

A detachable nozzle that attaches to the faucet with a flexible hose, giving you targeted spray for rinsing dishes or cleaning the sink. Pull-down sprayers are popular in modern kitchens.

4. Soap Dispenser (Optional)

A built-in pump located next to the faucet that dispenses dish soap directly from a refillable bottle under the sink.

5. Drain Opening and Strainer

The drain hole at the bottom of the basin is a standard 3½ inches across—universal for all kitchen sinks. The basket strainer sits inside this opening and catches food debris to prevent clogs. Most strainers are removable and include a stopper to fill the sink.

Under-Sink Plumbing: The Hidden System

6. Tailpiece

The tailpiece is a short, straight pipe that connects directly below the strainer (or garbage disposal) and directs water downward toward the trap. It’s typically 1½ inches in diameter. If you have a double-bowl sink, a tee fitting connects both tailpieces together before reaching the trap.

7. Garbage Disposal (Optional)

A motorized unit installed between the sink drain and the P-trap that grinds food waste into fine particles that can flow through the plumbing. It connects directly to the sink’s strainer body on one side and the tailpiece on the other.

Important: Disposals don’t use sharp blades—they use impellers and a shredder ring to break down food. Never put your hands inside a running disposal.

8. Dishwasher Drain Hose (Optional)

A flexible hose that connects the dishwasher to either the garbage disposal or a tee fitting on the drainpipe. It directs wastewater from the dishwasher into your home’s drainage system.

9. Water Supply Lines

Two flexible hoses (one hot, one cold) that connect from your home’s plumbing to the faucet. They typically have shut-off valves so you can turn off water to the sink for repairs. The hot supply is usually on the left, cold on the right.

10. P-Trap

The curved U-shaped pipe under the sink—so named because it looks like a “P” when viewed from the side. This is the unsung hero of your kitchen plumbing and has two critical jobs:

1. Holds water to block sewer gases—the bend always retains a little water, creating a seal that prevents nasty odors from rising up through the drain
2. Catches debris—the curve also traps small objects that accidentally fall down the drain, making them easier to retrieve before they cause a clog

The P-trap typically includes a cleanout (a removable plug) at the bottom for easy access to clogs.

11. Wall Tube / Waste Arm

The horizontal pipe that connects the P-trap to the drainpipe inside your wall, carrying wastewater to your home’s main sewer line. A decorative piece called an escutcheon covers the hole where the pipe enters the wall.

Simple Diagram: Kitchen Sink Parts

Here’s a visual breakdown of where everything sits:

ABOVE THE COUNTER:
┌──────────────────────────────┐
│  [Faucet]                     │
│  [Spout]          [Sprayer]   │
│  [Controls]                   │
│  ┌──────────────────────────┐ │
│  │       SINK BASIN        │ │
│  │                          │ │
│  │       [Drain/Strainer]   │ │
│  └──────────────────────────┘ │
└──────────────────────────────┘

UNDER THE COUNTER:
         ┌─────────┐
         │Strainer │
         │  Body   │
         └────┬────┘
              │
    ┌─────────┴─────────┐
    │   Tailpiece        │
    └─────────┬─────────┘
              │
    ┌─────────┴─────────┐
    │   Garbage Disposal │(optional)
    │   (if installed)   │
    └─────────┬─────────┘
              │
    ┌─────────┴─────────┐
    │   P-Trap (J-bend) │  ← holds water = gas barrier
    └─────────┬─────────┘
              │
    ┌─────────┴─────────┐
    │   Wall Tube       │
    └─────────┬─────────┘
              │
          into wall

Supply side (water in):

Main water line → Shut-off valves → Hot/Cold supply lines → Faucet

Quick Reference Table

FAQ

What are the basic parts of a kitchen sink?

The basic parts include the sink basin, faucet with controls, drain and strainer, tailpiece, P-trap, and water supply lines. Additional optional parts include a sprayer, garbage disposal, and dishwasher connections.

What is the curved pipe under the sink called?

It’s called a P-trap (or J-bend). It holds a small amount of water to create a seal that prevents sewer gases from entering your home.

What’s the difference between a bathroom and kitchen sink drain?

Kitchen sinks use a basket strainer that catches food debris. Bathroom sinks use pop-up stoppers that open and close with a lift rod. Kitchen drains are also larger—1½ inches vs. 1¼ inches for bathrooms.

What part of the sink prevents clogs?

The strainer catches larger food particles. The garbage disposal grinds food into fine particles. The P-trap catches debris that makes it past the strainer. Regular cleaning of all three prevents clogs.

How do I turn off water to my kitchen sink?

Look for the two shut-off valves under the sink (one for hot, one for cold). Turn them clockwise to close. If your sink doesn’t have them, turn off your home’s main water supply.

What’s the most confusing part of your sink plumbing—the P-trap, the disposal, or something else? Drop your questions in the comments below!

References

Kitchen Sink Parts and Plumbing Resources:

• HomeTips — How Kitchen Sink Drain Plumbing Works
• Angi — All the Parts of Kitchen Sink Plumbing
• Homedit — Parts of Kitchen Plumbing: Under Your Sink
• FS Drainage — Main Parts of a Kitchen Sink
• Angi — Complete Guide to the Parts of a Sink
• Ruvati — Parts of a Sink: The Ultimate Guide
• Ace Hardware — Sink Parts & Drain Repair