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Why Your Sink Smells Like Sewage

Why Your Sink Smells Like Sewage (Even After You Clean It)

Stephanie Carwell - 04/21/2026

You clean your sink.
You rinse it.
Maybe you even use a cleaner…
…but the smell is still there.

If your sink smells like sewage — especially in homes across Columbia and Lexington — the problem usually isn’t what you think. And in most cases, surface cleaning won’t fix it.

The Smell Isn’t Coming From the Sink

What many homeowners don’t realize is:

👉 The smell is usually coming from inside the drain line, not the sink itself.

Over time, buildup forms along the walls of your pipes:

  • Grease
  • Food debris
  • Soap scum
  • Bacteria

This creates a layer that can start to rot — producing a strong sewer-like odor.

Grease buildup in a drain causing sewage smell

Why It Keeps Coming Back

You may notice the smell returns quickly after cleaning. That’s because:

  • Cleaners only treat the surface
  • They don’t remove buildup deep in the pipe
  • Bacteria continues growing below the drain

This is especially common in kitchen sinks.

Other Possible Causes

1. Dry or Weak P-Trap

If a drain isn’t used often, the water barrier can evaporate. This allows sewer gas to rise into your home.

2. Venting Issues

Blocked vent pipes can cause sewer gases to push back through drains.

3. Developing Drain Blockage

If you’re also noticing:

  • Slow draining water
  • Gurgling sounds
  • Odors getting stronger

There may be a restriction forming in your drain system.

👉 Learn more about professional drain cleaning

Dry P-trap diagram showing how sewer gas enters the home

When It’s More Than Just a Smell

If the odor is combined with:

  • Multiple drains smelling
  • Sewer smells in other areas
  • Water backing up

This could indicate a larger plumbing issue. In some cases, leaks can also contribute to odors.

👉 Learn more about leak detection

215 Peach Grove Circle Elgin SC plumbing inspection

What Actually Fixes It

The real solution depends on the cause:

  • Buildup → professional drain cleaning
  • Dry trap → running water
  • Vent issue → inspection
  • Blockage → clearing the line

Temporary fixes usually don’t last.

When to Call a Plumber

If the smell keeps returning or gets worse, it’s time to have your system inspected.

Freedom Plumbing Inc. serves:

  • Columbia
  • Lexington
  • Irmo
  • Chapin
  • West Columbia
  • Cayce

👉 View service area

Call (803) 447-0471

Final Thoughts

If your sink smells like sewage even after cleaning, the issue is likely deeper in your plumbing system.

Addressing it early prevents bigger problems — and eliminates the smell for good.