Why does my shower drain smell foul?

Author: Prof. Kelton Adams MD  |  Last update: Wednesday, July 1, 2026

Build-up Of Biofilm Biofilm is a thin, slimy layer of bacteria that can grow from all the water, soap, shampoos, and body oils that go down the drain. This can then accumulate inside the pipes, causing your shower drain to smell like rotten eggs.

How do I get rid of the sewer smell in my shower drain?

One approach is to first pour a cup of baking soda and then a cup of white vinegar down the drain. After letting the mixture set for 15 to 20 minutes, run hot water into the drain to clear it. Utilizing a solution of one part water and one part chlorine bleach is another option.

Why does my shower drain smell like rotten?

If there's biofilm buildup on the fixtures, pipes, or drains, this is most likely caused by bacteria. It's gross and smells like rotten eggs. Surprisingly, this happens because of hair that's washed down the drains every time someone takes a shower. Bacteria like to feed on the particles and debris that hair attracts.

Why does my shower drain smell but not blocked?

In conclusion, sewage gasses, biofilm accumulation, bacterial development, and P-trap drying up can all be responsible for the foul odour emanating from a shower drain that appears to be unclogged.

How do you get the rotten smell out of a drain?

Pour 1⁄2 cup of baking soda into the smelly drain. Follow with 1⁄2 cup of white vinegar and let it fizz for 10-15 minutes. Flush the drain with boiling water to clear residue and odors. A dried-out P-trap can allow sewer gases to escape.

Shower Drain Smells Like a Sewer? Quick Easy Fix

Why should you never use baking soda and vinegar to unclog a drain?

Baking soda is abrasive, which, when used in large quantities, will cause the drain more damage. Additionally, the acidic nature of vinegar can eat away rubber and metal, damaging the plumbing. As these products break down the pipe and connectors in the plumbing in your home, it will cause more clogs over time.

Why does my drain smell like something died?

A build-up of organic matter can include small food particles, grease, hair and soap scum from bathroom and kitchen sinks or showers – as mentioned these small particles are not always enough to cause a blockage however they can become stuck to the inside of the pipes they will then begin to rot and creates gas as a by ...

How do you unblock a smelly drain?

Boiled water: Boil a saucepan of water or vinegar and slowly pour it down your smelly drain until you have half left. A few minutes later pour cold water into the drain then finish by pouring in the rest of the boiling water or vinegar. Trap: Manually clean out the P-trap under your sink.

How to clean a P-trap in a shower?

How To Clean Shower Waste Trap?
  1. Use a screwdriver to take off the drain cover.
  2. Wear gloves and use pliers to extract any hair or gunk you can reach.
  3. Pour a pot of boiling water down the drain to break up soap and grease.
  4. Mix 1/2 cup of each, pour it down, and let it sit for 15 minutes. ...
  5. Use a plunger for stubborn clogs.

Why does my bathroom sink drain smell but not clogged?

The presence of bacteria thriving in the moist, organic-rich environment of the drain can contribute to the offensive odor. Proper maintenance, regular cleaning, and the use of natural or commercial drain cleaners can help mitigate these issues and keep sink drains smelling fresh.

Why does my drain smell funky?

Infrequently used drains and sinks will dry out, allowing these odors (usually a rotten egg, sewer, or occasionally gas, chemical or solvent odor) to escape. The solution to this problem is simple—run water in all sinks periodically or pour water down floor drains from time to time (once a month is recommended).

What is best for unclogging a shower drain?

First, if you have metal pipes, pour boiling water down the drain. Then remove hair from the drain. If that doesn't work, use a mixture of vinegar and baking soda. If the clog persists, use a plunger, plumber's snake or chemical drain opener.

What does a shower P-trap look like?

P-traps, named after their shape, contain a u-shaped bend that filters wastewater as it enters a plumbing system. The trap is connected to a sink, bathtub, and shower with a J-bend on one end and exits into your drainage system. The J-bend is the section of the p-trap that resembles the letter J.

What neutralizes the smell of sewage?

Charcoal-based odor absorbers or baking soda can be placed near the source of the odor or in the affected rooms to absorb and neutralize the smell.

How to check shower p-trap?

You can check the p-trap yourself rather easily. First, look into the drain with a flashlight. You should be able to see some water. If you do not see water, the p-trap water level is likely too low.

Why does my shower drain smell like cat pee?

The p-trap could be dirty, or covered with a biofilm. A good cleaning and refilling the trap should be sufficient. The p-trap could be clogged. A clog in the p-trap is easier to resolve than a clog in the drain pipe, but it can still be a job for the professionals if you're not used to doing such home maintenance.

How do you fix a smelly shower drain?

Vinegar, Baking Soda and Hot Water

A concoction of white vinegar, baking soda, and hot water will help to eliminate odours from smelly shower drains effectively, as well as removing a buildup of grease, bacteria, and any other biological material residue (as long as the blockage is not severe).

What does a bad P-trap smell like?

A regular sewer-gas smell is just a bad stink with a definite odor of feces and sometimes a rotten-egg (hydrogen sulfide) smell and/or a moldy mustiness too.

How do you clean a P-trap without removing it?

Pour some baking soda down your drain and then pour boiling water down after. Sometimes this will clear the clog. Use a plunger on your sink drain to try to force the clog out of the trap.

Why does my drain smell rotten?

A common cause of a bad smell is simply bacteria. This usually occurs in indoor bathroom drains and sinks, as bacteria can come from hair, dirt or products that have gone into the drain. There are ways to prevent this build-up including bathroom drain traps.

What is the best chemical for smelly drains?

Bleach is highly effective in killing bacteria and other microbes causing the foul smell. However, it should be used sparingly to avoid damage to your plumbing system. Steps: Pour a cup of bleach down the drain.

Can I leave Mr. Muscle drain Gel overnight?

Using innovative drain unblocking technology, Mr Muscle's new biodegradable formula delivers the power to unclog bathroom drains in just 5 hours. Use it at night, let it work its magic and wake up to freely flowing drains.

How do you fix a smelly drain?

One option for how to clean smelly drains is to use a combination of 1 litre of boiling water, 1 cup of white vinegar and 2 cups of baking soda. Pour the baking soda down the drain, followed by the boiling water to dissolve it. Add the vinegar and insert the drain plug.

Why does my shower water smell like sewer?

If you begin to smell a sewage-like odor, then your P-trap may not be holding water as it should. In most cases, this is a minor, easy-to-solve issue. If you rarely use the shower, there is a chance the water in the P-trap has evaporated. You can fix a dry P-trap simply by running the water for a bit.

Can smelly drains make you ill?

Blocked drains can bring foul smells

But, more often than not, a bad smell will not have long-term health implications. However, these foul smells can cause headaches, fatigue, irritability and stress-induced anxiety-which will only get worse the longer a blocked drain is left untreated.

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