Step-by-step fix
Step 1: Make sure the strainer is really the problem
- Look at the tub drain and confirm the strainer itself is rusted through, cracked, badly corroded, missing, or no longer threads in tightly.
- Check whether the issue is only the visible strainer or if the drain body below it also looks damaged, loose, or badly out of round.
- If the tub is draining slowly, pull out any hair and debris first so you do not mistake a clog for a bad strainer.
- Set a rag in the tub so dropped tools do not chip the finish.
If it works: You know the visible tub drain strainer needs replacement and the drain opening below it appears usable.
If it doesn’t: If the drain shoe below the strainer is cracked, spinning freely, or badly corroded, this repair may need a larger drain assembly replacement instead of just a new strainer.
Stop if:- The drain body below the strainer is broken or severely rusted.
- The tub surface around the drain is cracked or unstable.
- You cannot tell whether the threads in the drain opening are still intact.
Step 2: Remove the old tub drain strainer
- Dry the area so your tool does not slip.
- Fit a tub drain wrench or drain key into the strainer and turn counterclockwise to back it out.
- If the crossbars are damaged, try gripping carefully with needle-nose pliers to start the turn without bending the drain opening.
- Work slowly and keep pressure centered so you do not twist the drain shoe below the tub.
If it works: The old strainer comes out without damaging the drain opening.
If it doesn’t: If the strainer is stuck, apply steady pressure and clear away visible corrosion or soap buildup before trying again. Avoid prying against the tub finish.
Stop if:- The entire drain body starts turning with the strainer.
- The crossbar breaks off and leaves the strainer shell jammed in place.
- You have to use so much force that the tub finish or drain body may be damaged.
Step 3: Clean the drain opening and threads
- Pull away old plumber's putty, sealant, hair, and soap residue from the top of the drain opening.
- Use a plastic putty knife or flat screwdriver gently to clean the seating surface where the new strainer will rest.
- Wipe the threads and surrounding area clean and dry so the new strainer can start straight.
- Check for stripped threads, cracks, or heavy corrosion inside the drain opening.
If it works: The drain opening is clean, smooth on top, and ready for the new strainer.
If it doesn’t: If the new strainer will not start by hand later, recheck for leftover putty or damaged threads in the drain opening.
Stop if:- The drain threads are stripped or missing.
- You find a crack in the drain body.
- The metal is so corroded that the new strainer will not have solid material to thread into.
Step 4: Prep and thread in the new strainer
- Compare the new tub drain strainer to the old one for diameter, thread style, and depth before installing it.
- If your strainer uses plumber's putty, roll a small rope of putty and press it under the flange of the new strainer.
- Set the strainer into the opening and turn it clockwise by hand first to avoid cross-threading.
- Once it is threading smoothly, snug it with the drain tool until it sits evenly and firmly against the tub surface.
- Wipe away any excess putty that squeezes out around the flange.
If it works: The new strainer threads in smoothly and sits flat without wobbling.
If it doesn’t: If it binds after a partial turn, back it out and restart by hand. A strainer that will not thread smoothly is usually the wrong fit or is cross-threaded.
Stop if:- The new strainer does not match the old one closely enough to start cleanly.
- The strainer rocks because the drain opening is distorted.
- Tightening the strainer causes the drain body below to move.
Step 5: Clean up and let the seal settle
- Remove excess putty or residue from the tub surface so the area is clean and easy to inspect.
- If you used plumber's putty, give the installation a short settling period before a full test so the flange stays seated.
- Make sure the strainer opening is clear and no scraps of putty or debris fell into the drain.
If it works: The new strainer is cleanly installed and ready for testing.
If it doesn’t: If the strainer loosens while cleaning up, snug it again gently with the drain tool.
Stop if:- The strainer will not stay tight after light snugging.
- The tub surface around the drain is flexing or cracking.
Step 6: Test the repair in real use
- Run water into the tub for a minute and watch around the strainer for movement or gaps.
- Let the tub drain and confirm water flows through normally without the strainer shifting.
- If your tub has an access panel and you can safely view the drain below, check for any sign of leaking during and after the test.
- Use the tub normally on the next bath or shower and recheck that the strainer stays tight.
If it works: The strainer stays secure, the tub drains normally, and there are no signs of leakage or movement.
If it doesn’t: If the strainer loosens, leaks, or will not stay aligned, remove it and recheck fit, threads, and sealing material. If the drain body is moving or leaking below, the repair likely needs a deeper drain assembly fix.
Stop if:- Water is leaking below the tub.
- The drain body shifts when the tub is used.
- The new strainer repeatedly loosens even when installed correctly.
Replacement Parts
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FAQ
Do I need plumber's putty for every tub drain strainer?
Not always. Many tub drain strainers are installed with plumber's putty under the flange, but some replacement parts may use a different sealing method. Follow the instructions that come with the replacement part.
What if the old strainer will not unscrew?
Try a proper tub drain wrench or drain key first. If the strainer is seized, work slowly and avoid twisting the whole drain body. If the crossbar breaks or the drain body starts moving, stop and plan for a larger drain repair.
How do I know if I bought the wrong replacement strainer?
If it will not start threading by hand, sits unevenly, or does not match the old strainer's diameter and thread pattern, it is likely the wrong fit. Match it to your exact drain sewer before ordering.
Can I replace just the strainer if the tub still drains slowly?
Only if the strainer is damaged. A slow drain is often caused by hair and soap buildup farther down the line. Clear the clog first so you do not replace a part that is not causing the problem.
Why does the new strainer keep loosening?
That usually points to damaged threads, the wrong replacement part, movement in the drain body below the tub, or a strainer that was not tightened evenly. Recheck fit and thread condition before trying again.