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Shower Drain Smells Bad? 4 Causes, the Free Fix, and What to Buy

A smelly shower drain is usually hair and soap scum rotting, or a dry trap letting sewer gas up. Clear it free, then add an enzyme cleaner.

By Jamilur Rahman Updated November 5, 2026 · 6 min read

Time
25 min
Cost
Under $20
Difficulty
Easy
A shower floor drain with its cover lifted off and a thin film of slime on the metal ring on white tile
In this guide
  1. Quick answer
  2. Free vs. permanent fix
  3. What you'll need
  4. Why it happens
  5. Try this first (free)
  6. When free fixes aren't enough
  7. Buy the fix
  8. What each smell usually means
  9. What to skip
  10. FAQ
  11. Related problems

Quick answer

Why does my shower drain smell? Most often, hair, soap scum and skin oils rot a few inches down, or a dry trap lets sewer gas come up. Pull the cover and the hair, scrub the drain walls, flush with hot water and run water in any shower you do not use. An enzyme drain cleaner then digests the film that feeds the smell, which is what stops it returning.

Free fix vs. permanent fix

Free fix · 25 minutes

Clear it, scrub it, flush it

  • Lift the cover and pull out the hair
  • Scrub the drain walls with an old brush
  • Flush with very hot tap water, never boiling
  • Run water in unused showers once a week

How long it lasts: A few weeks to a few months. Hair and soap scum build again, so the smell comes back.

Most readers choose Permanent fix
Enzyme drain cleaner (illustration)
Illustration

An enzyme drain cleaner

Enzyme cleaners use enzymes and friendly bacteria that break down hair, soap scum and body oil instead of burning through them. Used regularly, they keep the pipe walls clean so there is nothing left to rot, and they are gentler on pipes than caustic cleaners.

What to get: Enzyme drain cleaner

How long it lasts: Used monthly, it keeps the film from building, so the smell stays away for months.

Check price on Amazon

As an Amazon Associate I earn from qualifying purchases.

What you'll need

  • Rubber gloves

    For pulling out hair and slime

    You have it

  • Old toothbrush or bottle brush

    For scrubbing the drain walls

    You have it

  • Baking soda and white vinegar

    A quick clean, not a stand-in for the enzymes

    You have it
  • Barbed plastic drain strip (illustration)
    Illustration

    Barbed plastic drain strip

    Pulls out hair your fingers cannot reach

    Check price
  • Our pick
    Enzyme drain cleaner (illustration)
    Illustration

    Enzyme drain cleaner

    Digests the film that bacteria feed on

    Check price
  • Silicone shower drain hair catcher (illustration)
    Illustration

    Silicone shower drain hair catcher

    Keeps hair out so the film cannot build

    Check price

Why it happens

1

Hair and soap scum rotting in the pipe

Hair, soap, shampoo and dead skin build a slimy film inside the drain. Bacteria feed on it and give off a rotten-egg or musty smell, strongest when warm water runs.

2

A dry trap

A U-bend under every drain holds a plug of water that blocks sewer gas. In a guest or upstairs shower nobody uses, that water evaporates in a few weeks and sewer gas rises.

3

A vent problem

Drains need air from a roof vent to keep the trap water in place. A blocked vent makes the shower gurgle and can pull sewer gas through. This is a plumber's job.

4

The water heater, not the drain

If only the hot water smells like rotten eggs and the cold is fine, the cause can be bacteria in the water heater tank. Flushing the tank or having the anode rod checked can fix it.

Try this first (free)

Do these in order, starting with the simplest.

  1. Lift the cover and pull the hair out

    Tool used: Barbed plastic drain strip

    Unscrew or pop off the cover. Wearing gloves, pull out the hair and slime you can reach. A barbed strip goes deeper than your fingers.

    Barbed plastic drain strip (illustration)
    Illustration

    Tool for this step

    Barbed plastic drain strip · Pulls out hair your fingers cannot reach

    Check price on Amazon

  2. Scrub the drain walls

    Tool used: Old toothbrush or bottle brush

    Use an old toothbrush or bottle brush with warm water and a little dish soap on the visible walls and the underside of the cover. Rinse well.

  3. Flush with hot water

    Tool used: Baking soda and white vinegar

    Run very hot tap water for two minutes. Pour in a quarter cup of baking soda, then half a cup of white vinegar, wait 15 minutes and flush again. Do not use boiling water, which can soften PVC joints and crack porcelain.

  4. Refill the trap in unused showers

    In a guest or upstairs shower, run the water for a minute once a week. That refills the trap, so sewer gas stays below.

  5. Add an enzyme cleaner at night

    Tool used: Enzyme drain cleaner

    Follow the label. Most say to pour it in before bed so no water runs for six to eight hours. Wait a day after any vinegar or bleach, or the enzymes will not work.

    Enzyme drain cleaner (illustration)
    Illustration

    Tool for this step

    Enzyme drain cleaner · Digests the film that bacteria feed on

    Check price on Amazon

When free fixes aren't enough

If the smell is gone for a day and then returns, the film is deeper than a brush reaches, and an enzyme cleaner works on it over hours. If you smell sewer gas in several bathrooms, or the shower gurgles when you flush the toilet, the vent or main line may be blocked, so call a plumber. If you smell rotten eggs all over the house or think it may be natural gas, leave the house and call your gas company from outside.

Buy the fix

Still stuck after the free fixes? These are the products we would look at.

Our picks compared
PickProductFixesWho it's forBuy
Best pick
Enzyme drain cleaner (illustration)
Illustration
Enzyme drain cleaner
the slimy film in the pipe that bacteria feed on Anyone whose shower drain still smells after the hair is out, or who gets the smell every month. Check price
Upgrade pick
Silicone shower drain hair catcher (illustration)
Illustration
Silicone shower drain hair catcher
hair that feeds the smell and clogs the pipe Long-haired households and shared showers. Check price
Best pick
Enzyme drain cleaner (illustration)
Illustration

Enzyme drain cleaner

Fixes: the slimy film in the pipe that bacteria feed on

Look for: Enzyme or bacteria based, not caustic; Labeled safe for pipes, septic systems and shower drains; Light scent, so it does not just mask the smell; Clear overnight-use directions.

Who it's for
Anyone whose shower drain still smells after the hair is out, or who gets the smell every month.
Honest downside
The drain is fully blocked and water will not go down. An enzyme cleaner is not a clog remover, so clear the clog first.
Check price on Amazon
Upgrade pick
Silicone shower drain hair catcher (illustration)
Illustration

Silicone shower drain hair catcher

Fixes: hair that feeds the smell and clogs the pipe

Look for: A size and shape that match your drain, so measure first; Soft silicone that wipes clean; A lift-out design that does not make you touch the hair.

Who it's for
Long-haired households and shared showers.
Honest downside
Your drain has a stopper you cannot remove. Match the type before you buy.
Check price on Amazon

As an Amazon Associate I earn from qualifying purchases. We don't show prices because they change, so use the button to see today's price.

How we picked: How we picked: this page is based on plumbing and drain-care guides, product instructions from enzyme cleaner makers, and the problems and fixes people report in reviews. We do not test products by hand.

What each smell usually means

  • Sewer or sulfur: dry trap, vent problem or rotting film.
  • Rotten eggs from hot water only: the water heater.
  • Musty or mildew: soap scum and damp drain walls.
  • Urine: old film, or leaks around the toilet base.
  • Onions: sewer gas, so check the trap first.

What to skip

Bleach down the drain and air fresheners

Bleach on a hair film often lightens the smell for a day and can harm some pipes and finishes. It also gives off toxic gas if it meets vinegar or ammonia. A drain air freshener hides the smell without touching its source.

Frequently asked questions

Why does my shower drain smell like sewage or sewer?
A sewer smell usually means the trap is dry or the vent is blocked, not that sewage is leaking. Run water for a minute to refill the trap. If it returns or the drain gurgles, have a plumber check the vent.
Why does my shower drain smell like rotten eggs or sulfur?
Bacteria feeding on hair and soap give off hydrogen sulfide, which smells like rotten eggs. Clean the drain first. If only the hot water smells, the water heater is the likely source.
Why does my shower drain smell like urine or mildew?
A urine-like or musty smell usually comes from old soap scum and bacteria on the drain walls. Scrub, flush with hot water and use an enzyme cleaner. If it is strongest near the toilet, check the toilet base and grout.
Why does my shower drain smell but not clog, or only when water runs?
Running water stirs up the film coating the pipe, and it pushes trapped air and gas up through the drain. A drain that empties fine can still have dirty pipe walls.
Why does my upstairs shower drain smell, or smell like onions?
An upstairs shower is often the one nobody uses, so its trap runs dry. Run the water for a minute. An onion-like smell is also sewer gas, so treat it the same way and call a plumber if it stays.

As an Amazon Associate I earn from qualifying purchases. Affiliate disclosure

Enzyme drain cleaner (illustration)
Illustration

Our pick: Enzyme drain cleaner

Check price