How to Get Rid of Smelly Drains
(Fast Fixes + When to Call a Plumber)

If your drain smells bad, you’re not alone — and no, it’s not something you should just live with. A smelly drain is your plumbing system trying to tell you something. Sometimes it’s harmless buildup you can fix in minutes. Other times, it’s a warning sign of a blocked drain, sewer gas issue, or a plumbing fault that needs professional attention. This guide breaks it down properly:
  • What different drain smells actually mean
  • Simple DIY fixes that do work
  • Clear signs it’s time to call a plumber (before it gets worse)
Let’s get straight into it.

What Does Your Smelly Drain Actually Smell Like?

Before pouring anything down the drain, identify the smell. Different odours point to different problems.

Rotten Egg or Sulphur Smell

This usually means sewer gas escaping past a dry or faulty P-trap. It can also indicate a deeper sewer issue. This smell should never be ignored.

Musty or Mouldy Smell

A damp, earthy smell often points to biofilm buildup, mould, or mildew inside the drain. Common in showers and bathroom sinks.

Rancid or Garbage Smell

This is typically caused by food waste, grease, and organic debris rotting inside the pipes. Kitchen sinks are the usual culprit.

Sewage Smell

A strong sewage odour may indicate a blocked drain, venting issue, or sewer line problem. This is a clear sign to call a plumber.

Blocked Drains Caused by Hair, Soap Scum, and Food Scraps
What It Smells Like Most Likely Cause Risk Level What You Should Do
Rotten eggs / sulphur Sewer gas escaping due to a dry or faulty P-trap High Run water to refill the trap. If the smell continues, call a licensed plumber immediately.
Sewage smell Blocked drain, venting issue, or sewer line problem Very High Stop DIY fixes and book a plumber. This can become a health hazard.
Musty / mouldy Biofilm, mould, or mildew buildup inside the drain Low Clean the drain opening and flush with baking soda and vinegar.
Rancid / garbage Food waste, grease, or organic debris trapped in pipes Low Flush with boiling water and use a natural cleaning solution.
Chemical / sharp Reaction from drain cleaners or trapped chemical residue Medium Flush with clean water. Avoid mixing chemicals. Call a plumber if it persists.

This table helps you identify the problem fast — and avoid guessing or using the wrong fix.

Common Causes of Smelly Drains

1. Gunk and Bacteria Buildup

Hair, grease, soap scum, and food scraps slowly coat the inside of pipes. Over time, bacteria feed on this debris and release foul-smelling gases.

2. Mould or Mildew

Small leaks or constantly damp pipes create the perfect environment for mould growth, especially under sinks or inside floor wastes.

3. Dry or Faulty P-Trap

If a drain isn’t used often, the water seal in the P-trap can evaporate, allowing sewer gases to rise back into your home.

4. Blocked or Slow Drains

Partial blockages trap waste and stagnant water, leading to unpleasant odours and slow drainage.

5. Plumbing Installation Errors

Incorrect pipe gradients, poor venting, or DIY plumbing mistakes can cause ongoing smell issues that won’t disappear with home remedies.

How to Fix a Smelly Drain Yourself (When It’s Safe to Try)

Drain Cleaning

Step 1: Clean the Drain Opening

Remove visible debris such as hair, food scraps, and soap buildup from the drain cover and opening.

Filling It with Boiling Water

Step 2: Flush with Boiling Water

Slowly pour boiling water down the drain to loosen grease and break down residue. Repeat once or twice if needed.

Vinegar & Baking Soda

Step 3: Use Baking Soda & Vinegar

Pour half a cup of baking soda followed by half a cup of vinegar into the drain. Let it fizz for 15–20 minutes, then flush with hot water.

Running Water

Step 4: Run Water in Unused Drains

If the smell is coming from an unused sink, shower, or floor drain, simply running water for a minute may refill the P-trap and stop sewer gas.

These methods work well for minor buildup and maintenance — but they won’t fix serious blockages or sewer issues.

When DIY Won’t Work (And You Should Call a Plumber)

Call a licensed plumber if:

  • The smell keeps returning after cleaning
  • Multiple drains smell at the same time
  • You notice gurgling sounds or slow drainage
  • The odour smells like sewage or rotten eggs
  • There’s water backing up or pooling

Persistent smells usually mean a blocked drain, damaged pipe, or sewer connection issue. DIY solutions can make these problems worse if pushed too far.

How Often Should You Clean Your Drains?

As a general rule:

  • Bathroom and kitchen drains: monthly maintenance
  • Use drain strainers to catch hair and food scraps
  • Avoid pouring grease or oils down the sink

Regular cleaning helps prevent fatbergs, blockages, and long-term odour problems.

Need Help with a Smelly Drain in Newcastle?

If you’ve tried the basics and the smell won’t go away, it’s time to bring in a professional.

The Plumbing and Electrical Doctor specialises in:

  • Smelly and blocked drains
  • Drain inspections and clearing
  • Sewer and stormwater issues
  • Emergency plumbing services

Our licensed plumbers know exactly what causes drain odours — and how to fix them properly the first time.

Call 131091 to book a local plumber in Newcastle today.

Final Thoughts

A smelly drain isn’t just unpleasant — it’s often an early warning sign of a plumbing issue. Acting early can save you from bigger repairs, health risks, and costly damage.

If the smell doesn’t disappear with basic cleaning, don’t ignore it. A professional inspection can identify the real cause and keep your plumbing system running smoothly.

 

THE DOCTOR GETS IT DONE

• Licensed & Local • Fast, Reliable Service • 24/7 Emergency

Speak to a Plumber – 13 10 91

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