How to Replace a Bathtub Drain | Complete DIY Swap

Replacing a bathtub drain involves removing the old stopper and basket, cleaning the opening, sealing the new flange with plumber’s putty or silicone, installing the new assembly with a rubber gasket, reconnecting the overflow linkage, and testing for leaks.

A drip or a stuck stopper means it’s time to swap the whole tub drain. The project takes most DIYers about an hour with basic tools and a $15–$35 kit. The same steps work for the four common drain types found in US homes, and the full procedure breaks into three clear phases: removal, installation, and leak testing. If you expect a battle with a corroded old flange, a dedicated drain wrench makes the job much easier.

What You Need: Tools, Materials, and Cost

Standard US tub drains use a 1½-inch pipe setup, and a basic replacement requires a short tool list. Most hardware stores carry everything under $40 for the whole project.

Tools

• Screwdriver (for overflow plate and setscrews)
• Adjustable pliers or locking pliers
• Drain wrench (strainer wrench or tub drain key) — fits the crossbars inside the flange
• Needle-nose pliers (alternative to drain wrench)
• Putty knife
• Pipe wrench (for pipe connections below the tub)
• Caulking gun (if using silicone sealant)

Materials and Sealants

• Plumber’s putty: Standard seal under the flange; roll it into a pencil-thin rope before applying
• Clear silicone sealant: Alternative to putty; requires 1-hour cure before a leak test
• Rubber gasket: Sits inside the drain hole underneath the tub; must fit snugly
• Plumber’s tape (PTFE): For threaded overflow and pipe connections
• Bath waste and overflow kit: Includes new drain, gasket, overflow plate, and linkage

US price range (2024–2025): Basic tub drain kit $15–$35, premium kit $40–$80, drain wrench $10–$25, plumber’s putty $5–$10, silicone sealant $6–$12.

Remove the Old Drain

The removal method depends on your stopper type, but every style starts with the stopper set to the open position.

• Toe-touch (foot-lock): Unscrew the cap counterclockwise. No setscrew involved.
• Lift-and-turn: Remove the knob, then the setscrew underneath. Twist the entire stopper counterclockwise to free it.
• Trip-lever: Remove the overflow faceplate screws. Pull the plate and linkage out of the overflow opening.
• Push-pull: No unscrewing — simply pull the stopper straight out.

Once the stopper is out, insert a drain wrench into the crossbars inside the flange and turn counterclockwise. No drain wrench? Clamp needle-nose pliers onto a crossbar and turn those with standard pliers. After the basket loosens, pull out the old gasket and scrape away any remaining putty from the tub surface.

Install the New Drain Assembly

The new flange goes in from above, the gasket from below, and the overflow gets reconnected to keep your stopper working. Find the right bath drain kit that matches your tub material before starting.

1. Apply sealant: Roll plumber’s putty into a pencil-thin rope and wrap it around the underside of the new flange. If you use silicone instead, apply a clean bead under the flange rim.
2. Insert the drain: Place the flange into the drain hole from the top of the tub.
3. Install the gasket: From underneath the tub, slide the rubber gasket into the drain hole opening. It must sit snugly against the flange’s underside.
4. Align and tighten: Align the shoe elbow and gasket underneath, then catch the threads from inside the tub. Tighten with pliers or a strainer wrench — do not over-tighten, or the flange may crack or threads may strip.
5. Reconnect the overflow: Align the overflow assembly to the overflow hole. Attach the linkage to the trip-lever faceplate, insert the plunger linkage, and screw the overflow plate back on. Secure slip nuts and washers.
6. Connect pipes (if needed): Attach the tailpiece, P-trap, and waste pipe using plumber’s tape on threaded connections. Connect the waste pipe to the home’s plumbing system.

Common mistakes include skipping old-gasket removal, over-tightening, applying putty too thickly, or forgetting to reconnect the overflow linkage — any of these will mean redoing the work.

Test for Leaks

Closing the drain and running an inch or two of water is the only reliable check. Mark the water line with painter’s tape and wait one hour — if the level holds, the flange seal is sound. Then drain the tub and watch every connection (drain pipe, tailpiece, P-trap) while water flows. If you used silicone sealant, let it cure for a full hour before filling the tub. Skip this test and a slow leak behind the tub can cause floor damage before you notice anything.

FAQs

Do I really need a drain wrench, or will pliers work?

A drain wrench fits the crossbars inside the flange and gives the best leverage for loosening a stuck basket. Needle-nose pliers clamped onto a crossbar can work if the flange isn’t corroded, but the wrench is cheap and turns a potentially frustrating job into a quick one.

Can I replace a tub drain without going underneath the tub?

On most standard alcove tubs, yes — the work is done from above (removing the stopper, unscrewing the basket) and through the overflow opening. You may need access below only if the P-trap or waste pipe requires replacement, but the drain swap itself is accessible from the top.

Should I use plumber’s putty or silicone sealant?

Plumber’s putty is the standard choice because it forms a reliable seal immediately and excess wipes away easily. Clear silicone works well for acrylic tubs or porous porcelain where putty can stain, but it requires a 1-hour cure before the water test. Both are fine — choose based on your tub material and whether you want to wait for cure time.