Why Is My Bathtub Draining Slowly? (Causes and Fixes)

A slow-draining bathtub is most commonly caused by a hair clog forming inside the drain pipe. Other causes include soap scum buildup, a malfunctioning drain stopper that is partially blocking flow, or in rare cases, a problem further down in the plumbing system. Most slow drains can be fixed at home without a plumber.

Cause 1: Hair Clog (Most Common)

Hair combines with soap residue to form dense blockages inside the first few inches of your drain pipe. This is the cause of slow drains in the vast majority of cases. The fix: remove the drain stopper, pull out visible hair with pliers or a drain snake, then flush with hot water. To prevent recurrence, install an in-drain hair catcher like TubShroom.

Cause 2: Soap Scum Buildup

Soap, shampoo, and conditioner residue gradually coats pipe walls, narrowing the passage. This buildup also creates a sticky surface that traps hair. The fix: pour half a cup of baking soda and half a cup of vinegar into the drain monthly, wait 15 minutes, and flush with hot water.

Cause 3: Faulty Drain Stopper

Some bathtub stoppers, particularly trip-lever and push-pull types, can become misaligned and partially block the drain even when in the open position. The fix: inspect the stopper mechanism and adjust or replace if needed. TubShroom Ultra Plus includes an optional StopShroom plug that replaces broken or missing stoppers.

Cause 4: Deeper Plumbing Issues

If clearing the visible drain does not resolve slow drainage, the issue may be further in the plumbing system, such as a blocked vent pipe or main sewer line problem. This is less common and typically requires a professional plumber with a camera inspection tool.

Prevention Is Easier Than Fixing

The vast majority of slow-draining bathtubs are caused by preventable hair clogs. Installing a drain hair catcher is the simplest way to avoid the problem entirely. TubShroom has protected over 10 million drains worldwide and costs less than a single bottle of chemical drain cleaner.

Written by: TubShroom Drain Care Team
Specialists in hair clog prevention solutions used by millions of households.

We were featured in a Redfin article! Check it out here: Common Causes of Clogged Drains and Fixes | Redfin & Rocket