Clearing a slow bathtub drain in an older house
Older San Gabriel tubs drain through brass or galvanized piping that narrows with age.
Updated · 3 min read
The quick version
Most slow tubs are hair caught at the stopper or overflow linkage. If cleaning those does not help, the trap or the old drain pipe beyond it is narrowing, and a small drain cable or professional rooting clears it.
Sections
Why older tubs slow down
San Gabriel's median home dates from 1957. Tubs in houses that age often drain through drum traps or galvanized piping that collects soap scum and rust on its rough inside surface.
Hair binds with that buildup. Even after the stopper is cleaned, the pipe stays half-closed.
Start at the stopper
Pop-up stoppers lift out or unscrew. Trip-lever tubs have a plunger on a linkage behind the overflow plate; remove the two screws and pull it up.
Clean hair from both. Many slow tubs drain normally after this alone.
Look for a drum trap
Some older houses have a round metal drum trap near the tub, with a cap flush in the floor or behind an access panel. It collects hair and sludge and rarely gets cleaned.
When the line needs rooting
If the tub and the bathroom sink both slow down, the clog is likely past the trap in a shared branch. A drain cable through the overflow or a cleanout reaches it.
Galvanized drain arms that have rusted nearly shut cannot be cabled open for long. Replacing that short section is the lasting fix.
Questions we hear
Should I use chemical drain cleaner on an old tub?
Caustic cleaners can damage old metal pipes and make the repair hazardous. Mechanical clearing is safer.
Why does my tub gurgle when the toilet flushes?
They likely share a drain, and a partial clog or venting issue is pulling air through the tub trap.
How do I keep hair out of the drain?
A simple hair catcher over the drain and a monthly cleaning of the stopper keep most clogs away.