What’s That Musty Smell Under the Sink? Here’s How to Get Rid of It
If there’s a musty smell under your sink, you’re not alone. At Greg’s Plumbing, we get this call all the time—and the good news is, it’s usually easy to fix once you know what’s causing it.
1. It Could Be a Leak You Don’t See
Even a slow drip from the faucet or drain pipe can cause mold to grow under your sink. The area stays dark and damp, creating the perfect environment for that musty odor.
Check for:
- Water stains on the cabinet floor
- Warped wood or bubbling laminate
- Visible moisture around joints or shut-off valves
2. Trapped Moisture or Poor Ventilation
Sometimes the problem isn’t a leak—it’s steam or humidity that never dries out. If you store cleaning supplies or plastic bins under the sink, airflow is limited.
Fix it fast:
- Pull everything out
- Wipe down the space with vinegar or a mold cleaner
- Leave the cabinet doors open overnight
3. A Clogged Drain Could Be Sending Smells Back Up
When food or gunk builds up in the pipes, it doesn’t just slow drainage—it can start to smell like mildew or worse.
Pro tip: Pour boiling water down the drain, followed by baking soda and vinegar. If that doesn’t help, it’s time for a professional clean-out.
4. The P-Trap Might Be Dry
If it’s a sink that doesn’t get much use, the P-trap (that curved pipe under the sink) may have dried out. Without water in the trap, sewer gases can leak back into your home.
Quick fix: Run water for 30 seconds. That should reseal the trap.
When to Call a Plumber
If you’ve cleaned the area and the smell keeps coming back—or you notice black spots, soft wood, or leaks—it’s time to bring in a professional. Mold can spread fast under the surface, and slow leaks turn into big repairs if left alone.
Still smelling something off?
Let Greg’s Plumbing take a look before it gets worse. We handle everything from slow leaks to full drain replacements, fast and clean.
Get in Touch
Whether it’s a one-time issue or a full system refresh, we’re here to help.
→ Contact Greg’s Plumbing Now for expert plumbing services in Hamilton and peace of mind that lasts.
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