What you're actually replacing

A bathtub drain has two parts: the strainer body (the visible ring and basket that sits in the tub) and the drain assembly (the pipes and fittings underneath). Most replacements mean removing the strainer body and the tailpiece—the short pipe that connects it to the plumbing below. You may also replace the overflow tube if it's corroded or leaking.

The job takes two to four hours if you're working with standard plumbing and no surprises. You'll need basic tools: a screwdriver, adjustable wrench, plumber's wrench (or a second adjustable wrench), a putty knife, and a bucket. If the drain is stuck or corroded, add penetrating oil and extra time. If the pipes below the tub are cast iron or the connections are soldered, stop and call a plumber—those require specialized tools and skills.

Key Takeaways

  • The strainer body sits inside the tub; the tailpiece and trap sit underneath—you'll be working from both sides.
  • Shut off the water supply to the overflow before you start, and have a bucket ready to catch old plumber's putty and water.
  • The strainer body is held in place by putty and a locknut underneath; both must come out before the old drain lifts free.
  • New drains come with new putty or sealant; never reuse old putty, and follow the manufacturer's instructions for the specific product.
  • If pipes are soldered, cast iron, or stuck fast, call a plumber rather than risk damaging the tub or creating a leak.

Gather your materials and prepare the space

Before you touch anything, lay a towel or old sheet under the tub to protect your floor and catch spills. Place a bucket underneath the drain opening below the tub—old putty, water, and debris will fall. Have your new drain kit ready; most kits include the strainer body, tailpiece, overflow tube, and a tube of plumber's putty or silicone sealant. Read the instructions that came with your kit, because some brands use putty and others use sealant, and the steps differ slightly.

Turn off the water supply to the overflow mechanism if your tub has one. This is usually a valve under the sink or in the basement. If you can't find it or it doesn't shut off cleanly, you can still work—just be careful not to disturb the overflow tube while water is running. Have a flashlight ready; you'll need to see under the tub, and most bathrooms have poor lighting in that spot.

Remove the old strainer body and putty

The strainer body is held in place by plumber's putty around its base and a locknut underneath. Start from above: use a putty knife to scrape away all the old putty around the strainer rim. Work slowly and scrape toward the center so you don't scratch the tub. Once the putty is gone, you'll see the strainer body sitting in a clean ring.

Now go underneath the tub. You'll see the locknut—a large hexagonal nut that holds the strainer body in place. Use your plumber's wrench or adjustable wrench to turn it counterclockwise. If it's stuck, spray penetrating oil around the nut and wait 15 minutes before trying again. Once the nut is loose, unscrew it by hand. The strainer body will now lift out from above. Set it aside.

Disconnect the tailpiece and overflow tube

The tailpiece is the short pipe that screws into the bottom of the strainer body opening. If you haven't already removed it, use your wrench to unscrew the coupling nut that holds it to the trap (the U-shaped pipe below). Water will spill—that's why the bucket is there. Once the tailpiece is free, pull it out and set it aside.

The overflow tube runs from a hole in the tub wall down to the drain assembly. It's usually held by a single screw or clip. Locate it, remove the fastener, and gently pull the tube free. If it's corroded or cracked, you'll replace it with the new one from your kit. If it's in good condition and your kit doesn't include a new one, you can reuse it—just make sure the connection at the drain assembly is clean and tight.

Install the new strainer body and seal it

Clean the drain opening in the tub thoroughly. Use a rag to wipe away any old putty, debris, or corrosion. The surface must be dry and clean for the new sealant to stick. If your kit includes plumber's putty, roll it into a rope about the thickness of a pencil and press it around the underside of the new strainer body's flange (the flat ring). If your kit includes silicone sealant, explore a bead around the flange according to the manufacturer's instructions.

Lower the new strainer body into the drain opening from above. Press it down firmly so the putty or sealant spreads evenly. From underneath, hand-screw the locknut onto the threads until it's snug, then use your wrench to tighten it another quarter turn. Don't over-tighten—you'll crack the tub. Wipe away excess putty or sealant from around the strainer rim with a damp rag. Let the sealant cure for the time specified in your kit instructions (usually 24 hours for putty, 1 to 2 hours for silicone) before running water.

Reconnect the tailpiece and overflow

Screw the new tailpiece into the bottom of the strainer body by hand until it's snug. Then use your wrench to tighten the coupling nut that connects it to the trap. Hand-tighten first, then give it a quarter turn with the wrench. Again, snug is the goal—over-tightening can crack fittings or strip threads.

Reconnect the overflow tube to the drain assembly. If you're reusing the old tube, make sure the connection is tight and there's no corrosion at the joint. If you're installing a new tube from your kit, follow the kit instructions for the correct depth and fastening method. Most overflow tubes slide into a fitting and are held by a set screw; tighten it firmly but not so hard that you strip the threads.

Test for leaks before you finish

Once the sealant has cured, fill the tub with a few inches of water and let it sit for 10 minutes. Watch the area under the tub for drips. If you see water coming from the strainer body connection, the putty or sealant didn't seal properly—drain the tub, remove the strainer body, and redo the seal. If water is coming from the tailpiece or trap connection, tighten the coupling nut a bit more. If water is coming from the overflow tube connection, tighten that fastener.

Once the tub holds water without leaking, drain it and run water down the overflow to test that path as well. The overflow should drain smoothly without backing up. If it does back up, the tube may be kinked or the connection may be too tight. Adjust as needed. After everything checks out, you're done.

When to call a plumber instead

If the old strainer body won't budge even after soaking with penetrating oil, the pipes below the tub are soldered copper or cast iron, or the tub itself is cracked around the drain, stop and call a plumber. Forcing a stuck drain can crack the tub or damage the pipes. Soldered and cast-iron connections require specialized tools and experience. A plumber can handle these situations without creating a bigger problem.

Also call a plumber if you open up the area under the tub and find water damage, soft wood, or mold. These signs mean there's been a leak for a while, and the structure may need repair before you install a new drain.

Frequently Asked Questions

Can I replace just the strainer body without touching the pipes below?

Yes, if the tailpiece and trap are in good condition. You'll still remove the old strainer body and putty, then install the new one. The tailpiece stays in place. This is faster and cheaper than a full drain replacement, but it only works if the pipes aren't leaking or corroded.

What's the difference between plumber's putty and silicone sealant?

Putty is moldable and sets firm; it's traditional and straightforward to remove later if you need to. Silicone sealant is waterproof and flexible, so it handles movement better. Check your drain kit to see which one it includes, because they're not interchangeable—using the wrong one can cause leaks.

How long do I have to wait before using the tub after replacing the drain?

If you used plumber's putty, wait 24 hours. If you used silicone sealant, check the tube—most cure in 1 to 2 hours, but some take longer. Running water before the sealant is fully cured can wash it out and create a leak.

What if water leaks from under the tub right after I finish?

Drain the tub when ready and identify where the water is coming from. If it's the strainer body, the seal didn't take—remove the strainer and redo the putty or sealant. If it's the tailpiece or trap connection, tighten the coupling nut. If tightening doesn't stop it, the fitting may be cracked and needs replacement.

Do I need a plumber's wrench, or can I use two adjustable wrenches?

Two adjustable wrenches work fine. One holds the nut still while the other turns the coupling. A plumber's wrench is designed for the job and gives you better grip, but it's not required if you already have two adjustable wrenches.