Bathroom sink drain parts include the flange, stopper, drain body, gaskets, locknut, tailpiece, and P-trap, plus the pop-up linkage rod system.
Ordering replacements gets confusing fast, but every bathroom sink drain uses the same core components. Here’s the complete breakdown of the parts you’ll find on a typical US bathroom sink drain.
The Core Drain Assembly Parts
The assembly starts at the basin and runs down to your home’s plumbing. These parts appear in every bathroom sink, whether it has a pop-up stopper or a lift-and-turn plug.
- Drain flange or strainer basket — the visible metal or plastic piece seated in the sink basin opening.
- Stopper or pop-up stopper — the plug that seals the drain so the basin holds water.
- Drain body — the main vertical housing connecting the flange to the plumbing below.
- Gaskets and washers — rubber or plastic seals creating watertight connections between parts.
- Locknut — the large nut that cinches the assembly together from underneath the sink.
- Tailpiece — the straight tube continuing from the drain body down to the trap.
- P-trap — the curved pipe holding water to block sewer gases from rising into the bathroom.
- Trap arm — the horizontal pipe carrying wastewater from the P-trap to the wall drain line.
Home Depot’s sink parts guide names the same lineup: strainer basket, strainer flange, P-trap, strainer nut, rubber gasket, and friction gasket. Plumber’s putty is typically applied under the flange to seat it against the basin edge.
Pop-Up Stopper Linkage Parts
Most bathroom sinks use a pop-up stopper controlled by a rod behind the faucet. When you lift the rod, linked pieces push the stopper up. The linkage system has four main parts:
- Lift rod — the vertical rod behind the faucet you pull up or push down.
- Clevis — the flat metal strap connecting the lift rod to the pivot rod.
- Pivot rod — a horizontal rod passing through the drain body to move the stopper.
- Pivot ball nut — the nut sealing the pivot rod where it enters the drain body.
- Rod clip and thumb screw — small connectors locking the rods together and securing the clevis to the lift rod.
Ideal Standard’s lavatory drain parts list uses the same vocabulary: trim, O-rings, stopper, tube, outer seal, slip washer, large nut, lift knob, thumb screw, clevis, rod clip, pivot ball nut, and rod ball assembly. Some manufacturers sell linkage parts as a complete kit with clevis, pivot rod, and clips.
What Part Is Actually Leaking?
Leaks trace to one of three spots: the seal under the flange, the gaskets between the drain body and the sink, or the slip-joint connections at the tailpiece and P-trap. At the basin level, a flange leak usually means the plumber’s putty or rubber gasket has failed. Under the sink, a leak where the tailpiece meets the drain body points to a worn slip washer or loose slip nut. Water dripping from P-trap joints means the washers inside the slip nuts have hardened or cracked.
One detail matters before ordering: overflow compatibility. Some drains work with an overflow opening in the basin, and some don’t. Check whether your sink has that small hole near the rim, then confirm the replacement drain is built for it.
Kitchen vs. Bathroom Drain Parts
Kitchen and bathroom sinks differ in ways that matter. Bathroom sink drains typically use a pop-up stopper and linkage rod system — the rod-and-clevis setup you operate from behind the faucet. Kitchen sinks more often rely on basket strainers or connect directly to a garbage disposal.
Calling every pipe under the sink a P-trap is the most common naming mistake. The tailpiece runs from the drain body to the trap, the P-trap is the curved section, and the trap arm carries water from the trap into the wall — three distinct parts with three distinct jobs.
Exact names vary by manufacturer. Some brands stamp specific part numbers on drain bodies rather than using generic terms, so if ordering for a specific model, bringing the old part — or its part number — to the store saves a guessing round.
Ready to buy what you need? We tested and ranked the best bathroom sink drain plumbing parts — our top picks for bathroom sink drains cover pop-up assemblies and replacement kits for standard US sinks.
FAQs
What is the metal piece inside the sink drain called?
The visible metal piece inside the basin is the drain flange, also called a strainer flange or strainer basket. It seats in the sink opening and holds the stopper. On pop-up drains, the flange is a single piece with a hole through which the stopper rod rises and lowers.
Do I need plumber’s putty to install a bathroom sink drain?
Plumber’s putty is commonly applied under the flange to create a watertight seal against the basin. Some manufacturers instead specify a rubber gasket for that job, and using the wrong sealing method can void the warranty or cause leaks. Check the installation sheet that comes with your specific drain before choosing.
Why does my bathroom smell like sewer gas?
A sewer gas smell usually means the P-trap water seal has broken, either from a leak, an improperly vented drain, or a trap that has dried out. The P-trap holds water that blocks gases from the home drain line. If the smell persists after running water, inspect the trap connections for leaks or cracks.
References & Sources
- Home Depot. “Parts of a Sink.” Identifies core drain components and the role of plumber’s putty.
- Lowe’s. “The Parts of Your Bathroom Sink.” Buying guide covering bathroom-specific drain terminology.
- Ideal Standard. “Lavatory Drain.” Parts list naming pop-up linkage components and seal pieces.
