When the kitchen sink drain drips, backs up, or smells, daily life slows down. Small issues—like a worn washer, cracked slip nut, wrong P-trap height, or a trap arm with no slope—can lead to leaks, clogs, and cabinet damage. The good news: most failures come from a few visible, fixable points under the sink.
This guide explains every kitchen sink drain part, how each component connects, and how to choose materials such as PVC, ABS, brass, or stainless. You’ll learn step-by-step installation and replacement, how to prevent leaks and odors, and how to keep water flowing smoothly. It also covers double-sink and disposal layouts, common troubleshooting, and answers to frequent questions like: What are the parts of a kitchen sink drain called? Are kitchen sink drains universal? What is a drain slip joint? What are the components of a kitchen sink? What is the rubber thing in the kitchen sink called?
Kitchen Sink Drain Parts: Quick Answers
Before diving into detailed diagrams and connections, this section gives you a fast overview of each part and what it does, so you can identify components quickly under the sink.
Core components at-a-glance (with functions)
From top to wall, here’s how the standard kitchen sink drain assembly is named and what each piece does:
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Basket strainer: The metal cup and grid you see inside the sink; it lets water through and holds back larger debris.
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Strainer flange: The ring that seals the basket to the sink; it forms the top waterproof joint.
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Rubber gasket/washer: The flexible seal between the flange and the underside of the sink; it stops leaks at the top.
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Locknut: The large nut that clamps the basket and gasket to the sink.
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Tailpiece (6–12 inches): The straight pipe that carries water from the basket to the trap.
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P-trap: The U-shaped curve that holds a water seal to block sewer gases.
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Trap arm (waste arm): The horizontal pipe from the trap to the wall drain.
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Slip joints (slip nuts and beveled washers): The hand-tight fittings that let you assemble, align, and disassemble without glue.
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Garbage disposal (optional): Replaces the tailpiece; grinds food; has a side inlet for the dishwasher.
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Dishwasher drain connection: The small hose connection—either to the disposal or to a tailpiece wye.
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Air gap (regional requirement): A small device on the sink deck that prevents dirty water from siphoning into the dishwasher.
Fast specs and code-friendly measurements
Use these common measurements to plan and check your setup. Always confirm local code.
| Item | Typical/Recommended Value |
| Sink drain opening | 3-1/2 inches (most kitchen sinks) |
| Tubular drain size | 1-1/2 inches (kitchen), adapters available |
| Tailpiece length | 6–12 inches (cut to fit) |
| P-trap to wall distance | Often within ~24 inches in standard cabinets (verify code) |
| Horizontal slope | 1/4 inch drop per foot of run |
| Slip joints | Use rubber or nylon beveled washers at compression points |
| Metal-to-metal threads | Use approved thread compound (not Teflon tape on basket threads) |
What are the parts under a kitchen sink called?
People use a few names for the same pieces. You’ll hear “tailpiece,” “P-trap,” “trap arm” or “waste arm,” “basket strainer,” “compression nut,” “slip washer,” and—for double sinks—a “baffle tee.” If you have a disposal, folks may mention the “splash guard” or “disposal baffle” too.
How the Drain Assembly Works (from Basket to Wall)
Once you know the names of each part, the next step is understanding how water actually moves through the system and where each seal matters in real-world use.
Flow path and sealing points
Water starts at the basket and passes through the strainer flange. A ring of plumber’s putty or a rubber gasket seals this top joint so water can’t creep under the sink deck. From the flange, water runs down the tailpiece into the P-trap. The trap holds a small pool of water in its curve. That water blocks sewer gases from entering the kitchen. From the trap, water moves through the trap arm into the wall’s drain and out to the main drain. Venting in the wall keeps air pressure balanced so the trap seal doesn’t siphon away.
Each joint has a seal to prevent leaks. At the top, the flange-to-sink seal is critical. Every slip joint—tailpiece to trap, trap to arm—has a beveled washer that compresses as you tighten the slip nut. These are your main leak points to check during install and after any bump or movement.
Leak-risk locations and why they fail
Leaks tend to show up where parts move or where seals age:
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Overtightened slip nuts can crack plastic and deform washers, causing slow drips.
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A missing or flipped beveled washer won’t seal the joint even if it feels tight.
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A misaligned trap arm puts side load on the joint, loosening the seal.
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Old putty or a dried gasket at the top flange can seep slowly and stain the cabinet.
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Bare metal threads without the right compound can weep.
If you fix or install a kitchen sink drain, always align parts first, hand-tighten, then add a small turn. Run hot and cold water for a minute, then wipe each joint with a dry paper towel and check again after a few hours.
Integrations: garbage disposal and dishwasher
A garbage disposal takes the place of the tailpiece and bolts to the basket or a special mounting ring. The outlet of the disposal points to the P-trap just like a standard tailpiece. If you connect a dishwasher, the hose often runs to a small inlet on the side of the disposal. There’s a thin “knockout” you must remove before attaching the hose. If you don’t, the dishwasher won’t drain.
If you don’t have a disposal, you can attach the dishwasher hose to a tailpiece wye with a small barb. For backflow protection, route the dishwasher hose with a high loop under the countertop or install an air gap, as your local code requires.
Do I need an air gap for my dishwasher?
In many places, yes. Regions that follow the Uniform Plumbing Code usually require an air gap on the deck. Some areas that follow the International Plumbing Code allow a properly secured high loop instead. Because rules vary by city and county, check with your local building department.
Materials and Sizing: PVC vs ABS vs Brass vs Stainless
With the flow path clear, choosing the right material becomes easier. This section compares durability, cost, and compatibility so you pick parts that fit your sink and local code.
Material pros/cons by use case
The material you choose affects price, ease of install, and longevity. It also affects how the parts look if the plumbing is visible.
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PVC is lightweight, easy to cut, and simple for DIY. It resists corrosion from common household water. It’s a top choice inside cabinets where looks don’t matter.
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ABS is black plastic with good impact resistance. It’s common in some regions and climates. It glues with a different cement than PVC in building drains, but the under-sink “tubular” ABS uses slip-joint fittings like PVC.
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Brass with chrome plating looks nice for exposed plumbing and handles heat well. It’s durable and repairable. It costs more and needs the right thread compound on metal-to-metal joints.
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Stainless steel is premium and resists corrosion. You’ll see it in commercial or upscale builds, often for the visible basket and flange.
Compatibility and code notes
Don’t glue ABS to PVC with standard cement; they need a listed transition cement or a mechanical adapter if you mix systems. Under the sink, you may still use tubular plastic or metal parts with compression joints even when the house drain is ABS or PVC. If you expect hot discharge (like dishwashers), make sure your chosen material and gaskets can handle the heat. In open vanities or islands, many people choose metal for the style and finish.
Sizing and fitment essentials
Most kitchen sinks have a 3-1/2 inch opening for the strainer. The sink drain parts under the bowl are usually 1-1/2 inch “tubular” size. Some prep or bar sinks are smaller, so check your sink’s manual. Tailpieces are commonly 6–12 inches long; cut them to fit your height and alignment. If your trap doesn’t reach the wall, extensions and slip couplings bridge the gap. Use adapters if you’re connecting to 1-1/4 inch lines from older installs.
Visual: side-by-side material table
| Material | Durability | Cost | Ease of install | Temperature tolerance (typical household use) | Best for | Maintenance |
| PVC | Good | Low | Easy | Good for hot tap water and dishwasher discharge | Hidden cabinets, DIY | Inspect washers; replace if brittle |
| ABS | Good | Low–Medium | Easy | Good for hot tap water and dishwasher discharge | Regions that favor ABS | Same as PVC |
| Brass (chrome) | Very good | Medium–High | Moderate | Very good | Exposed plumbing, heat tolerance | Periodic check of threads and finish |
| Stainless | Excellent | High | Moderate | Excellent | Premium or commercial | Minimal, inspect gaskets |
Note: Always follow manufacturer ratings for exact temperature and chemical limits.
Installation and Replacement: Step-by-Step
After selecting the proper components, here’s how to assemble and install everything correctly, from the basket to the trap, using techniques that prevent the most common leaks.
Tools, prep, and sealing best practices
A neat install prevents most callbacks and rework. Set out all drain parts before you start. Dry-fit everything and only tighten when aligned.
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Tools:
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Channel-lock pliers or adjustable wrench
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Plumber’s putty or the specified gasket/sealant
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Tape measure and small level
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Utility knife or tubing cutter
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Thread compound for metal-to-metal joints
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Bucket, towels, and a flashlight
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Best practices:
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Dry-fit, align, then tighten by hand plus 1/4–1/2 turn.
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Keep beveled washers facing the right direction (taper toward the joint).
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Support the trap during tightening so the washer seats evenly.
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For metal baskets, use putty unless the maker calls for a rubber gasket.
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Do not overtighten. Tighten only until leak-free under flow.
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Install a basket strainer, flange, and tailpiece
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Remove the old basket and clean the sink opening down to bare metal or composite. Any old putty will stop a good seal.
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Roll a thin rope of plumber’s putty and press it under the strainer flange (or place the supplied gasket if required). Set the basket in the sink hole.
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From underneath, slide on the rubber gasket, then the cardboard or friction washer (if included), then thread on the large locknut. Center the basket and snug the locknut evenly. Wipe away extra putty squeezed out at the top.
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Attach the tailpiece with its slip nut and beveled washer. Keep the tailpiece plumb. This makes trap alignment easier.
Assemble the P-trap and trap arm with proper slope
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Hold the P-trap up to the tailpiece and mark the trap arm length to the wall stub-out. Aim for a smooth path with no strain.
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Cut the trap arm square. Deburr the inside edge so the washer seats well.
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Slide slip nuts and beveled washers onto each joint in the right order. Connect the trap to the tailpiece, then to the wall elbow.
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Keep the trap seal centered under the tailpiece. The horizontal pipe (trap arm) should have about 1/4 inch fall per foot toward the wall.
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Hand-tighten all joints, then add a small turn with pliers. Run water and check. Re-tighten only if you see a drip.
How tight should slip nuts be?
Aim for hand-tight plus a small turn—about 1/4 to 1/2 turn with pliers. Overtightening can crush the washer or crack plastic. If it leaks, snug it a little more. If it still leaks, re-seat the washer and check alignment.
Troubleshooting Leaks, Clogs, and Odors
Even well-installed drains can develop issues over time. This section helps you diagnose problems quickly and fix the ones most homeowners encounter.
Leak diagnosis flow (top-down)
Start at the top and move down. Is water pooling around the basket? If yes, your strainer flange seal may be bad. Dry the area, run water, and look for a slow halo forming. If the top is dry, wipe each slip joint with a paper towel while water runs. A wet line under a nut points to a washer issue—re-seat or replace. Dye a cup of water with food coloring and pour it down. The color will show the first point of failure if you’re unsure. If the trap body itself drips, check for a hairline crack or a loose cleanout plug.
Clog hotspots and safe clearing
Most clogs form above the trap, at the basket, the tailpiece, or the inlet of the trap. For double sinks, the baffle tee can collect grease and debris. Clear clogs by removing the trap (place a bucket under it first) and cleaning out buildup. A small hand snake can break stubborn plugs. Avoid harsh chemicals, especially on metal parts, and be careful with boiling water on plastic. If you have a cleanout plug on the trap or wall, use it to feed a snake rather than pushing debris deeper.
Sewer gas and odor cures
If your kitchen smells like sewer, the trap seal may be dry. Run water to refill it. If the smell returns, you may have a vent issue pulling the seal down, or a slow leak above the trap letting odors out. Make sure the trap sits directly below the outlet; avoid odd angles that can siphon. Clean the inside of the pipes and the disposal’s splash guard to remove biofilm. Check the dishwasher hose routing; a proper high loop or air gap helps stop backflow odors.
Why does my kitchen sink smell like sewer?
Top causes include a dry P-trap, a blocked or missing vent, a loose slip joint above the trap, or bacterial buildup. Fix by restoring the water seal, checking venting, re-seating washers, and cleaning the drain surfaces.
Special Setups: Double Sinks, Disposals, and Air Gaps
If your kitchen uses a multi-bowl sink, a garbage disposal, or a dishwasher air-gap system, these layouts require a few extra rules—this section explains how to configure them correctly.
Double-bowl geometry and tees
For a double sink, both bowls often share one P-trap. A baffle tee connects the two tailpieces and sends flow to the trap. The baffle slows water from one bowl so it won’t shoot into the other. Keep both arms level with the correct pitch to the tee. Avoid two traps in series; most codes call for one trap serving the combined fixture arm.
Garbage disposal best practices
Mount the disposal level and tight so it does not vibrate the joints loose. If you hook up a dishwasher, remove the internal knockout in the disposal’s side inlet. Use the right hose adapter and clamp. Check that the disposal discharge lines up cleanly with the trap. Heavy units may need extra support to avoid stress on the fittings.
Dishwasher drain routing
Route the dishwasher hose with a high loop up under the countertop or to a code-required air gap on the sink deck. Secure the hose so it cannot sag. Connect the outlet from the air gap (or the loop) to the disposal or tailpiece wye. This routing stops dirty water from entering the appliance.
Can a garbage disposal share a P-trap?
Yes. The disposal and sink can share a single P-trap through a correctly oriented tee or baffle tee. Do not install two traps in a row; that can cause poor drainage and code issues.
Maintenance and Longevity: Prevent, Inspect, Replace
To keep your drain system working for years, simple periodic checks go a long way. This final section shows how to maintain parts, spot wear, and know when replacements are due.
Replacement intervals and wear signals
Rubber gaskets may last 3–7 years depending on heat, cleaners, and use. Plastic traps can last many years but should be replaced if crazed, stained, or warped. Metal parts with pitting or rust should be swapped out before they leak. If you re-tighten a joint more than once, consider a new washer or a better-quality part.
Preventive checklist
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Monthly: Rinse strainers, clean stopper seals, wipe the disposal splash guard.
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Quarterly: Remove the trap and clean out buildup if your sink drains slowly or you cook with oils.
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Annually: Re-seat the basket if you see staining under the flange; confirm slope and alignment; replace tired washers.
Smart habits and eco practices
Catch debris with a sink strainer and toss it in the trash. Avoid pouring grease down the drain; wipe pans with a paper towel first. Use enzyme-based cleaners sparingly if needed, and choose hot water flushes over harsh chemicals. For clogs, mechanical clearing is kinder to parts than caustic liquids.
FAQs
1. What are the parts of a kitchen sink drain called?
The parts of a kitchen sink drain are usually grouped as kitchen sink drain parts or key components of the home drain system. A standard assembly includes the basket strainer at the top, which catches debris before entering the drain, a tailpiece that carries wastewater downward, and the P-trap—one of the most essential drain parts sink owners rely on to block sewer gas. The trap arm connects the trap to the wall section of the plumbing. Slip joints hold everything together and allow easy removal for cleaning or repair. In some setups, a garbage disposal, dishwasher inlet, or air gap completes the system. Together, these kitchen sink components direct wastewater from the sink and the rest of the plumbing to the floor drain line efficiently. Understanding each part helps you troubleshoot leaks, plan a DIY project, or decide when a complicated upgrade might require professional help.
2. Are kitchen sink drains universal?
Kitchen sink drains are mostly standardized, but not fully universal. Most kitchen sink drain parts are designed for a 3.5-inch opening and 1.5-inch tubular pipes, which works for the majority of home sinks. However, bar sinks, older bathroom sinks, and some international models use different dimensions, meaning the drain system may need adapters or upgraded components. While the upper section (the basket and flange) tends to match most sinks, the bottom of the assembly—like the trap arm and waste line height—must align with your floor or wall outlet. This is why some installations require professional adjustment. If you're planning a DIY project, confirming measurements avoids misalignment and keeps wastewater flowing efficiently. A mismatched tailpiece or trap can cause leaks, poor function, or difficulty entering the drain properly. When all measurements match, the sink and the rest of the plumbing work smoothly, making repair and future upgrades easier.
3. What is a drain slip joint?
A drain slip joint is a key connector used in kitchen sink drain parts and many bathroom assemblies. It consists of a slip nut and a beveled washer that compresses as you tighten it, creating a watertight seal in the drain system. This feature allows easy removal for cleaning, repair, or upgrades without cutting pipes—ideal for any home project. Slip joints appear in several sections of the plumbing: between the tailpiece and trap, within the P-trap itself, and where the trap arm meets the wall. Because they allow small adjustments, they help align kitchen sink components efficiently, ensuring wastewater flows smoothly without stressing the pipes. A slip joint also lets you reposition or replace parts at the bottom of the sink when installing a disposal or other accessory. Although designed for DIY users, overtightening can deform the washer, so proper technique prevents leaks and avoids work that might otherwise require professional correction.
4. What are the components of a kitchen sink?
A kitchen sink includes both visible and hidden kitchen sink components. On the surface you have the basin, faucet, and lever-style handles. Below, the kitchen sink drain parts form the essential drain system that carries wastewater out of the home. These key components include the basket strainer, the flange, the tailpiece, the P-trap, and the trap arm leading to the wall’s drain section. Optional features include a garbage disposal, dishwasher inlet, and air gap, all of which help manage food particles and prevent contaminated water from entering the drain backward. Together, the sink and the rest of these parts create an efficient system that prevents odors and blockages. Whether you’re planning a repair or a full upgrade project, understanding how each part fits from top to bottom makes installation smoother and helps determine when the work may require professional help—especially if floor height or venting issues complicate alignment.
5. What is the rubber thing in the kitchen sink called?
The “rubber thing” in a kitchen sink typically refers to one of two kitchen sink drain parts. First is the rubber gasket beneath the sink, part of the core kitchen sink components that seal the basket strainer to prevent wastewater leaks. This gasket compresses between the sink and the rest of the assembly, keeping the drain system tight and efficient. The second possibility—common in homes with a disposal—is the rubber splash guard or baffle at the top opening. This flexible part stops debris from entering the drain too quickly and reduces noise while allowing food scraps to pass through. Both rubber components play important roles in the bottom section of the plumbing and often need replacement during repair or upgrade projects. Because these soft parts age faster than metal fittings, they’re easy to swap using simple tools, and most homeowners can DIY the task unless alignment issues require professional assistance.
References
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