Question

One of the showers in my home has a smell similar to cigarette smoke coming from the drain. Bleach in the drain 2 days in a row fixes it for about 2 weeks before it comes back. No smokers live nearby or in the home. What is this and how do I fix it?

Answer 1

The persistent smell of cigarette smoke coming from a shower drain, despite no smokers living nearby or in the home, can be puzzling. However, there are a few possible explanations for this issue:

1. Dry P-trap: The P-trap is a U-shaped pipe located beneath sinks, showers, and drains. It is designed to hold water, which acts as a barrier against sewer gases from entering your home. If a drain is not used frequently, the water in the P-trap can evaporate, allowing odors to escape from the sewer system and into your home. In this case, pouring bleach down the drain re-fills the trap temporarily but evaporates again after a few weeks, leading to the return of the smell.

Solution: To fix this issue, run water down the shower drain regularly to keep the P-trap filled. This can be done by running the shower or simply pouring water down the drain once a week or so.

2. Biofilm or Organic Matter: Over time, biofilm or organic matter can accumulate in the pipes and drains, leading to unpleasant odors. Even if there are no smokers in the vicinity, other substances may have accumulated and produced a similar smell.

Solution: To eliminate the biofilm or organic matter, you can try using an enzyme-based drain cleaner. These cleaners are designed to break down organic material and eliminate odors. Follow the instructions on the product for the best results.

3. Ventilation Issue: Another possibility is that there may be a ventilation problem in your plumbing system. Proper ventilation allows air to flow through the pipes, preventing the buildup of odors. If there is a ventilation issue, it could be causing the smell to travel back up the drain and into your shower.

Solution: If you suspect a ventilation issue, it's best to consult a professional plumber. They can inspect your plumbing system, identify any ventilation problems, and make the necessary repairs or adjustments.

If the issue persists or if you're uncertain about the cause, it's advisable to contact a plumber who can investigate the problem thoroughly. They will have the expertise to diagnose the issue accurately and recommend the most appropriate solution for your specific situation.