Your drain likely smells when you run water because of odor-causing bacteria and/or mold feeding on accumulated debris within your pipes. This process releases foul-smelling gases. Let's break down the common causes:
Common Causes of Drain Odors
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Bacteria Growth: Bacteria thrive in the damp, dark environment of your drain pipes, especially when food particles, hair, soap scum, and other organic matter are present. As they decompose this debris, they release hydrogen sulfide gas.
- Smell: This gas has a characteristic sewage or rotten egg odor.
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Mold Growth: Similarly, mold loves warm, wet places. If a clog forms and traps moisture, mold can grow on the debris.
- Smell: Mold growth contributes to a musty, unpleasant smell.
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Dry P-Trap: The P-trap is a U-shaped pipe under your sink designed to trap water and prevent sewer gases from entering your home. If a drain isn't used frequently, the water in the P-trap can evaporate, allowing sewer gases to escape.
- Smell: Sewer gas smells like rotten eggs or methane.
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Clogged or Dirty Drain Pipes: Build-up in the pipes can prevent proper drainage and cause stagnant water, further encouraging bacteria and mold growth.
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Biofilm: A slimy layer of bacteria and organic matter can coat the inside of your drain pipes. This biofilm traps debris and contributes to odors.
What to Do About Smelly Drains
Here's a simple solution to get rid of the smell:
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Flush with Hot Water: Run hot water down the drain for several minutes to dislodge some of the debris.
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Baking Soda and Vinegar: Pour 1 cup of baking soda down the drain, followed by 1 cup of white vinegar. Let it fizz for 30 minutes, then flush with hot water.
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Clean the Drain Stopper: Remove the drain stopper and clean any hair or debris caught on it.
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Check the P-Trap: If the drain hasn't been used in a while, run water to refill the P-trap. If the smell persists, consider loosening the P-trap (place a bucket underneath!) to clean out any accumulated sludge.
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Professional Help: If the problem persists, consider calling a plumber for a professional drain cleaning. They may use tools like a drain snake to remove stubborn clogs and biofilm.
