Reused Tub Gasket: Safe or Risky?
Replacing an old bathtub drain can make the tub look much better.
It can also raise a few plumbing questions.
One common question is about the rubber gasket under the tub.
A homeowner recently replaced an old push/pull tub drain.
After removing the drain, they wanted to replace the gasket under the tub.
The problem was finding the right size gasket.
The original gasket was solid rubber and about 1/4 inch thick.
Stores only had solid rubber gaskets that were about 1/8 inch thick.
So, the homeowner cleaned the old gasket and reused it.
Question
Is it okay to reuse the original bathtub drain gasket?
The old plumber’s putty was cleaned off.
The drain flange was tightened back down.
The home is built on a slab.
Answer
Yes, it may be okay if the old gasket is still soft, flat, and not cracked.
The gasket under the tub is very important.
It helps seal the drain shoe against the bottom of the tub.
If that gasket is damaged, water can leak under the tub.
Reusing the original gasket can work in some cases.
This is more likely when the gasket is still flexible.
It should not be brittle, split, crushed, or uneven.
A 1/4 inch gasket may have been used for a reason.
Some tub drains need that extra thickness.
A thinner 1/8 inch gasket might not seal the gap well.
Plumber’s putty usually goes under the drain flange inside the tub.
It is not the main seal under the tub.
The rubber gasket does that job below the tub.
Since this is a slab home, checking for leaks matters even more.
There may be little or no easy access under the tub.
A hidden leak can cause damage before it is noticed.
How To Check Your Work
- Fill the tub with several inches of water.
- Let it sit for 15 to 30 minutes.
- Release the drain and watch closely.
- Check nearby walls, floors, and ceilings if possible.
- Look for damp smells over the next few days.
If there is an access panel, inspect the drain area with a light.
If there is no access, watch for signs around the tub.
Soft flooring, stains, or odors can point to a leak.
You can also review general drain repair guidance from The Home Depot or learn more about plumbing systems from EPA WaterSense.
When To Replace The Gasket
Replace the gasket if it feels hard or cracked.
Replace it if it looks smashed or uneven.
Also, replace it if you see any sign of water.
If a 1/4 inch gasket is needed, check a plumbing supply house.
They often carry parts that big-box stores do not stock.
Bring the old gasket with you for a match.
In many cases, reusing the gasket is not ideal.
But it can be safe if the gasket is still in good shape.
The leak test is the real answer.
I’m Chris Mayer, writing for Plumbing 101.
