Causes of Sewer Gas Odour after Using the Shower

Sewer gas smells that are present after using the shower are an indicator that something is wrong with the drain vent or the drain itself.

If you notice such smells after using your shower, then you should start with diagnosing the root cause of the problem and deal with it effectively.

Sewer Gas Odour after Using the Shower


One way of diagnosing the issue is by eliminating the possible sources of sewer smells by inspecting the drain for common problems.

If you have basic knowledge about home plumbing, then you’ll be better placed to diagnose several issues that may affect your plumbing system. Check for the following plumbing issues:


Clogged Drains

Once you notice sewer smells from your bathroom after using the shower, check whether there’s a clogged drainage. Clogged drains are a common source of sewer odours. Once the drain clogs, water will not drain smoothly.

A lot of water will remain in the drain, thereby creating a favorable environment for mildew and mold to grow. Consequently, sewer odours will start backing up into the bathroom as a result of the clogged drain.

You can deal with this problem and prevent it from recurring by ensuring the drain remains functional at all times.

Test whether the drain is working properly by flushing your toilet, checking that the shower and tub are draining properly, and running water down the sink.

If water fails to run smoothly down the drain of any of these plumbing fixtures, then you probably have a clogged drain.


Shower Trap

The shower drainage should have a functional drain trap. Even other household drains such as the sinks require having a functional drain trap.

The trap is an elbow-shaped pipe that’s installed on the section between the drainage of a plumbing fixture and the branch or main sewer line. The trap works by retaining some water after flushing the drain.

The trapped water seals the drainage system to prevent sewer gasses from flowing back into the home. Ensure your shower drain has a trap. Also, confirm whether it’s installed properly.


Drain Vent

Every household drain should be connected to a working drain vent. The drain vent comprises of a pipe that goes through the attic or roof.

The top section of the pipe is left open to allow air into the drain. The air prevents wastewater from creating a vacuum within the drainage, thereby preventing the wastewater from backing up.

However, the drain vent can get clogged due to the accumulation of debris or blocks of ice.

You can easily check whether the drain vent is blocked. To do this, you’ll need to access the vent from the roof. You can use a garden hose to unclog it from the roof.

The drain vent looks like a metallic pipe with a diameter of around 2 inches. Thus, you’ll easily find it on the roof. In case it’s blocked, take a garden hose and run it through the vent opening.

Next, open the water supply connected to the hose to flush the drain vent. However, make sure that the water is draining and not backing up. The clog should be eliminated once the vent pipe drains the water.


Cracked Drain Pipes

Cracked drain pipes can also cause sewer gases to back up through the bathroom drain after using the shower. If the top surface of the drainpipe is cracked, sewer gases will escape through the crack before water does.

Thus, you’d hardly realize that the drain line is leaking. Check along the drain line for any holes or cracks that may be allowing sewer gases to escape.


Related Articles:

What Are Sewer Cleanouts?

A Guide on Doing Rough-In Bathroom Plumbing

How to Deal with Musty Odours from Drain Pipes

Why Is My New Toilet Smelling Like Raw Sewer?

A Guide for Troubleshooting and Repairing a Faulty Shower Faucet

How Does A Shower Drain Work?

By |2020-04-03T18:34:38+10:30November 22nd, 2019|Bathroom, General Plumbing|0 Comments

Leave A Comment