The short answer
Hair commonly collects around a bathtub stopper, but a slow tub can also have a deeper trap or branch-line restriction. Start with the removable stopper area. If cleaning it makes little difference, stop treating the visible opening as the whole problem.
Identify the stopper before removal
Lift-and-turn, toe-touch, trip-lever, and push-pull stoppers come apart differently. Photograph the assembly and use the maker’s instructions. Do not pry against the tub finish or remove the overflow plate unless you understand the linkage behind it.
Remove visible hair with a non-scratching tool while wearing gloves. Keep screws and linkage parts out of the drain.
Test the result
Run a measured, shallow amount of water and time how the level falls. Note whether the drain gurgles and whether another fixture changes the behavior.
| Result | What it suggests |
|---|---|
| Flow returns after stopper cleaning | Local hair buildup was the main restriction |
| Flow improves only slightly | More debris may remain in the trap or branch |
| Water backs up in another fixture | Shared drain restriction |
| Leak appears at ceiling below | Stop use; drain or overflow assembly may be leaking |
| Tub drains slowly and toilet gurgles | Branch or venting problem needs plumbing diagnosis |
Oatey’s bath-waste instructions treat the drain and overflow as one connected assembly and require leak testing. Avoid aggressive probing that can damage that assembly.
What not to do
Do not mix drain products, plunge after adding caustic cleaner, or open piping without telling the person doing the work what is in the drain. Do not push hair farther into the line with an improvised rigid object.
A hand-operated tool may be appropriate when its instructions match the drain and the stopper is safely removed. Stop if it binds, contacts an unknown fitting, or causes leakage.