You already understand the significance of regularly cleaning your bathroom. Yet, you might find that your bathroom sink still emits an unpleasant odor despite your diligent efforts. This is due to the fact that mold and mildew thrive in warm, humid conditions, making it an ideal scenario with continuous hot water usage, an enclosed area lacking proper ventilation, and growth mediums like soap scum accumulating on the bathtub or sink. A mold-infested environment can lead to allergic reactions, skin irritation, or other long-term health issues (particularly for individuals with asthma and other respiratory problems), so maintaining cleanliness is crucial. However, you might still detect a musty odor lingering around your sink even after scrubbing the basin, the drainage hole, and any pipes underneath. The culprit could be a neglected part of the sink: the overflow hole. Therefore, it’s essential to clean it thoroughly.
Mold, a type of fungus, can unexpectedly grow in various places; you might even need to rescue your bathroom towels if mold starts to develop on them. It stands to reason that mold or mildew could be concealed in a sink’s overflow drain, accessible through that small hole with an unfinished interior closest to you when you’re bending over the rim to spit out toothpaste. This dark, enclosed space is designed to handle the full flow rate of your faucet in case the primary drain is obstructed, ideally preventing a complete water overflow onto your bathroom floor. Mold can begin to form within 24 to 48 hours of water exposure on any damp surface, so it’s crucial to start cleaning if you detect an odor emanating from the sink’s overflow.
What you can do to address the mildew smell in your sink’s overflow drain
There are numerous notoriously difficult spots to clean in your bathroom that shouldn’t be ignored, from the bend behind the toilet to the upper corners of your shower. A sink’s overflow drain is particularly tricky due to its small access hole positioned at an awkward angle. While chemical biocides aren’t advised for routine mold cleanings, as they can emit toxic fumes without always sterilizing the entire growth, there are other solutions to pour down the drain to tackle the mold issue.
To start, acquire a heat-resistant funnel made of metal, silicone, or similar materials. Use this funnel to pour 1 cup of baking soda, followed by 1 cup of vinegar into the drain, causing the cleaning foam to expand throughout the enclosed space like a classic baking soda volcano experiment. After waiting about 15 to 20 minutes, flush the drain with boiling water, repeating the process until the musty smell is gone. Physical scrubbing is often necessary to ensure all the built-up mold is removed before allowing the space to dry out, so consider using pipe cleaners or a sink-cleaning brush to reach the gunk inside the overflow hole.
Ways to try and prevent smelly mildew from growing in your sink
Eliminating a mold infestation completely is challenging, as background spores often remain post-cleaning — and even dead mold can trigger allergic reactions if not fully eradicated. Given the difficulty of inspecting inside your sink’s drainage pipe to verify a thorough cleaning, your best approach is to follow preventive measures to keep mold from entering in the first place. As suggested, ensure exhaust fans are running during showers and maintain indoor humidity below 60%. A leaky sink can also foster mold growth due to constant water exposure, so promptly repair any pipes or faucets at the first sign of trouble.
It’s important to note that mildew isn’t the only odor potentially emanating from your sink. If you experience an unexpected sewage backup, the sink is a primary location where it might resurface — though it could also affect your shower, toilet, washing machine, or other pipe-connected appliances. In such cases, seal any drainage holes with a plug to prevent overflow into your bathroom, and contact a professional to resolve the home’s sewage system. Once the sewage issue is addressed, you can still pour cleaning products down the overflow hole to eliminate any lingering odors, ensuring your bathroom feels fresh again.
