Architectural Home Designs & Decorating Ideas

Master Plumbing Repairs by Understanding Your Kitchen Sink's Anatomy

Gabriela Connell
4 minute read

If you’ve ever struggled to fix a leaky faucet or unclog a blocked drain, you know how frustrating DIY sink repairs can be. But having a solid grasp of the anatomy of your kitchen sink’s plumbing can make a tricky repair job much more manageable.

When you understand the name and function of each component under your sink, you can more easily pinpoint problems and make fixes. Read on to become an expert in your sink’s anatomy!

Anatomy of a Kitchen Sink Drain

Let’s start from the top down by examining the parts that make up a typical residential kitchen sink drain assembly:

kitchen sink parts diagram

Sink Drain Opening and Strainer

At the bottom of your sink basin is the drain opening, which is covered by a removable strainer. This strainer basket catches food scraps and debris, preventing them from clogging pipes. The strainer assembly consists of a perforated cover and a flange that screws into the sink drain body. Unscrewing the flange allows access to the drain parts below for maintenance and repairs.


The tailpiece is the short, vertical length of pipe that connects to the sink strainer and extends down to the curved p-trap below. Most tailpieces are 1.5 inches in diameter and feature slip-joint connections. This means they slot together using compression washers, rather than threading or gluing. Extensions are available if your sink basin is extra deep.


This crucial U-shaped section of piping gets its name from its distinctive curved shape. The curve holds a small pool of water, which creates a water seal that prevents foul sewer gases from escaping into the home while allowing sink wastewater to pass through. For proper drainage, the p-trap must be installed at the correct downhill angle and height below the sink basin’s drain opening.

Trap Arm

The short, horizontal length of pipe after the p-trap is called the trap arm. It connects to the downward-slanting drain pipe that leads to the main sewer line. The ideal setup has a trap arm no longer than 24 inches that travels straight into the drain pipe. This keeps the velocity and flow high enough to flush out waste efficiently.

Kitchen Sink Plumbing Supply Lines

Now let’s examine the hot and cold water supply plumbing that feeds water up to your kitchen faucet:

Shut Off Valves

Mounted to the sink cabinet wall are the hot and cold water shut off valves. These allow you to turn on or off water flow as needed for repairs or emergencies. During normal operation, the shut off valves must be fully open. To stop all water, locate these valves and turn them clockwise until tight.

Supply Lines and Fittings

Flexible stainless steel braided pipes called supply lines carry pressurized hot and cold water up to the faucet. They connect to threaded fittings called shank tails at the faucet inlets. The other ends connect to the shut off valves via compression fittings sealed with nylon or rubber washers.


The sink faucet mixes hot and cold water to the desired temperature and controls water flow volume. Most kitchen faucets have a single handle that moves side-to-side and lifts up and down. Others have separate hot and cold handles. Faucets feature a removable spout head, one or two handle bodies, and an inner cartridge that maintains flow control.

Common Kitchen Sink Repairs

Now that you understand your sink’s inner workings, let’s go over some of the most typical DIY kitchen sink repairs:

Unclogging a Clogged Sink Drain

A slow-draining or completely clogged sink is one of the most annoying issues you can encounter. Start by using a heavy-duty plunger over the drain opening while sealing any overflow holes with rags. This creates suction to dislodge the clog. You can also try removing and cleaning the p-trap. For deeper clogs down the trap arm, use a drain auger or snake.

Replacing Supply Line Washers

If you notice leaking or dripping under the sink, the supply line compression fittings are often the culprit. Turn off the water and unscrew the bad washer. Bring the old one to the hardware store to match it up with a replacement washer, ensuring you get the correct size and beveled shape.

Installing a Garbage Disposal

For food waste grinding convenience, you can DIY the installation of a garbage disposal unit. Start by unplugging the drain pipes and dishwasher hose if connected. Mount the disposal by turning the mounting ring until tight against the sink flange using plumber’s putty for a seal. Then follow the wiring instructions to connect the electrical supply.

Fixing a Leaky Faucet

A faucet leak may come from the spout, handles, or connections. Carefully take the faucet apart to identify the source, then replace any faulty washers, O-rings, inner cartridge, or valve seats as needed. Use silicone grease on any rubber washers and be sure to put faucet components back in the right sequence.

We hope this deep dive into your kitchen sink’s anatomy provides the insight you need to tackle any plumbing issue like a pro. Knowing the name and job of each drain and supply fixture will build the confidence to diagnose and fix leaks, clogs, flow problems, and more.

For additional tips, always refer to the manufacturer’s instructions when servicing specific faucet or drain parts. And take all necessary precautions whenever shutting off main water lines or dealing with supply lines. With the right knowledge of your sink’s inner workings, you’ll keep your kitchen plumbing running smoothly for years to come!