How to Replace a Bathtub Drain Assembly

Step 1: Make sure the drain assembly is really the problem

1. Look for rust, cracks, stripped crossbars, a loose flange, or water leaking from the drain area when the tub is filled and drained.
2. Check whether the problem is at the drain opening itself, not just a worn stopper or a slow clog farther down the line.
3. If you can access the plumbing below or behind the tub, look for drips at the drain shoe while someone runs a small amount of water into the tub.

If it works: You have good reason to replace the bathtub drain assembly because the drain body or its seal is failing.

If it doesn’t: If the tub only drains slowly, try clearing the clog first. If only the stopper is broken, you may only need a stopper repair instead of a full drain replacement.

Step 2: Set up the tub and remove the old drain

1. Take out the stopper if it is removable so you can reach the inside of the drain body.
2. Lay a rag in the tub to protect the finish from dropped tools.
3. Insert the tub drain removal tool into the drain and turn counterclockwise with pliers or a wrench until the old drain body backs out.
4. If the drain is stubborn, apply steady pressure instead of jerking hard so you do not twist the piping below.

Step 3: Clean the opening and check the drain shoe threads

1. Scrape off all old plumber's putty, gasket material, and grime from the tub surface around the drain opening.
2. Wipe the area clean and dry so the new seal can sit flat.
3. Inspect the drain shoe threads below the opening for damage, heavy corrosion, or distortion.
4. Dry-fit the new drain body by hand for a turn or two to make sure the threads start cleanly, then remove it again.

If it doesn’t: If the new drain will not thread in smoothly by hand, recheck that you bought the correct replacement and inspect the shoe for thread damage.

Step 4: Seal and install the new bathtub drain assembly

1. Roll a small rope of plumber's putty and place it under the flange of the new drain, unless the replacement part specifically uses a different seal.
2. Set the new drain into the opening and thread it into the drain shoe by hand first to avoid cross-threading.
3. Tighten the drain with the removal tool until the flange sits snug and even against the tub surface.
4. Wipe away the excess putty that squeezes out around the flange.

Step 5: Reassemble the stopper and run a leak test

1. Reinstall the stopper or visible trim that came off during removal.
2. Close the drain and fill the tub with a few inches of water so the new seal is under standing water pressure.
3. Check below or behind the tub, if accessible, for any dripping around the drain shoe and nearby joints.
4. Open the drain and watch while the tub empties, since some leaks only show up during draining.

Step 6: Confirm the repair holds in normal use

1. Use the tub normally once or twice and pay attention to any damp smell, drips below, or water collecting around the drain opening.
2. Check that the stopper still opens and closes properly and that the drain empties without backing up around the flange.
3. Wipe the area dry after use and recheck later for any fresh moisture.

If it works: The bathtub drain assembly stays dry in real use, the stopper works, and the tub drains without leaking.

If it doesn’t: If moisture returns after normal use, inspect again for a poor flange seal, a loose stopper connection, or a leak from the overflow or drain piping nearby.