What size drain tailpiece do I need for my kitchen sink?

Kitchen sinks almost always use 1-1/2 inch OD tailpieces, which fit the standard 3-1/2 inch basket strainer body. Bathroom sinks typically use 1-1/4 inch OD tailpieces. Measure the existing tailpiece's outer diameter or check the strainer body thread size if you are unsure. Plastic tailpieces are often available in both sizes at hardware stores.

Why is my sink drain leaking at the tailpiece?

Tailpiece leaks are almost always at the slip-joint connections — the slip nuts at the top (strainer) or bottom (p-trap) connection. The rubber washers inside those connections compress over time and lose their seal. Hand-tighten the slip nuts first. If that does not stop the leak, unscrew the nut, replace the rubber washer, and retighten. If the pipe body itself is cracking or corroded, replace the tailpiece.

How long should a drain tailpiece be?

Standard tailpieces are 6 or 8 inches long. The correct length is whatever puts the p-trap inlet at a height where the trap can connect to the drain arm in the wall without extreme angles. If your p-trap sits unusually low, use a tailpiece extension to bridge the gap. Extensions slip onto the bottom of the tailpiece with another slip-nut connection.

Does replacing a drain tailpiece require a permit?

No permit is required to replace a tailpiece in kind. It is a standard plumbing maintenance repair that any homeowner can perform. Reconfiguring the entire drain assembly as part of a sink relocation or remodel may require a permit depending on the scope of work.

What is a dishwasher tailpiece?

A dishwasher tailpiece is a standard drain tailpiece with an added side branch — a small barbed nipple — that accepts the dishwasher drain hose when no garbage disposal is present. This branch has a plastic plug that must be removed before attaching the drain hose. It serves the same backflow connection role as the disposal's side inlet port.

Drain Tailpiece — Sink Drain Pipe Between Strainer and Trap

A drain tailpiece is a straight vertical pipe section that connects the bottom of a sink basket strainer or drain body to the p-trap inlet, forming the first segment of the sink drain assembly.

Drain Tailpiece diagram — labeled parts and installation context

What It Is

A drain tailpiece is a short length of smooth pipe — typically 1-1/2 inch outer diameter for kitchen sinks and 1-1/4 inch for bathroom sinks — that drops vertically from the strainer body to the p-trap inlet. It connects at the top via a slip nut and rubber or nylon washer that threads onto the strainer body tailpiece shank, and at the bottom via another slip-joint connection to the p-trap arm.

Tailpieces are commonly chrome-plated brass, ABS plastic, or PVC. Chrome brass is the traditional choice for exposed installations where the under-sink plumbing is visible, such as pedestal sinks and wall-mounted vanities. Plastic is widely used in concealed or budget applications. The standard length is 6 to 8 inches, but 12-inch extensions are available when the trap is positioned lower than usual due to cabinet depth or non-standard rough-in height.

Some tailpieces include a side inlet port — often called a tee tailpiece or dishwasher tailpiece — with a barbed branch connection sized for the dishwasher drain hose. This branch, typically 7/8 inch outside diameter, is used when no garbage disposal is present to receive the dishwasher discharge line. The branch port includes a removable plastic knockout that must be popped out before connecting the hose.

Types

Straight tailpieces are the most common form and consist of a plain tube with no branching connections. Tee tailpieces include a side branch for a dishwasher or secondary drain line. Flanged tailpieces have a built-in flange at the top that sits under the strainer body and seals with a gasket, eliminating the need for a separate slip-nut connection. Adjustable tailpieces telescope to allow fine-tuning of the vertical length without cutting.

Material options include 17-gauge chrome-plated brass for durability and appearance, schedule 40 PVC for chemical resistance, and ABS plastic for economy. Some specialty tailpieces are made from polypropylene for resistance to chemicals used in laboratory or darkroom sinks.

Where It Is Used

Tailpieces are installed on every sink — kitchen, bathroom, utility, bar — wherever a p-trap is required below the drain outlet. They are one of the most frequently replaced plumbing components because of their position in a wet, corrosion-prone environment directly below the drain opening where detergents, food acids, and standing water accelerate deterioration.

In double-bowl kitchen sinks, each bowl has its own tailpiece that connects to a tee fitting or continuous waste assembly before reaching the single p-trap. Bar sinks and prep sinks in islands also use tailpieces, often requiring longer runs to reach offset traps behind or beside the cabinet.

How to Identify One

Look under any sink. The vertical pipe running from the drain fitting at the bottom of the sink bowl down to the curved p-trap is the tailpiece. It is usually 6 to 12 inches long, smooth-walled, and secured with hand-tightened slip nuts at each end. The slip nuts are the chrome or white plastic ring fittings visible at the top and bottom connection points.

A corroded tailpiece may show green patina on brass or white mineral deposits on plastic. A leaking tailpiece often leaves water stains or a slow drip visible on the outside of the pipe near the slip-nut connections.

Replacement

Tailpieces are inexpensive — typically $5 to $15 — and require no special tools because slip nuts can be hand-tightened in most cases. A pair of slip-joint pliers helps when connections are corroded or over-tightened. Replace when the pipe is cracked, corroded through (common with thin chrome brass after 10 to 15 years), leaking at the slip joints despite new washers, or when reconfiguring the drain assembly for a new sink or disposal installation.

No permit is required for a like-for-like tailpiece replacement. Match the outer diameter (1-1/4 inch or 1-1/2 inch) to the existing strainer body and p-trap, and confirm the length before purchasing to avoid an unnecessary trip for an extension.