How to Clean a Bathroom Sink Overflow Hole

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In cleaning your sink, you take special care to remove buildup from your drain, mold from your faucet, and stains from the sink surface. You scrub, sanitize, and deodorize every inch of your bathroom. Your bathroom may be clean inside and out, but you might be forgetting one essential feature that is standard in every sink: the sink overflow hole.

The sink overflow hole is probably the most underrated feature of a bathroom sink. Chances are that you have never considered the feature to be purposeful or important. You may not even have noticed it. However, this is far from the truth, as the overflow hole acts as a drainage when water in the sink reaches near maximum capacity. 

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What is a Bathroom Sink Overflow Hole?

Usually located beneath the faucet, the sink overflow prevents spillage of water on the floor when the sink gets filled. It is usually placed just a few inches under the full capacity of the sink. The bathroom sink overflow hole also introduces air into the sewer system, causing a suction that allows water to drain from the sink quicker. 

Without a sink overflow, the sink can quickly fill up and spill all over your bathroom, as the water drains slower than the faucet flows. Sewage backing up from clogged pipes would also make their way onto your floors without the purpose of an overflow draining system. 

Helpful Tip: Some sinks have caps or stoppers over their overflow holes so the homeowner can fill up the sink as needed. So if you cannot locate the overflow drain, check behind these caps and stoppers as you may have a sink model that features an overflow drain cover.

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The Main Causes of Dirt

As it is rarely noticed, the overflow hole is rarely cleaned well. Dirt and mold make their way into the overflow hole, eventually leading to grime build up. Since the overflow hole is usually undisturbed, debris can stick to its walls and sides and can get dried and crusty. The overflow hole can also harbor many types of bacteria, some being harmful to your health. 

Some of the main causes of a dirty overflow hole include general dust particles that find their way into the sink overflow, food and organic material dropped into the overflow hole, and oils from conditioners and lotions that congeal over time.

Mold is also a common problem in overflow holes. The warm, dark, moist environment allows mold and mildew colonies to thrive, especially as the overflow hole is rarely disturbed. With these growths, the sink hosts various organisms that can give you allergies and make you sick when you inhale their spores. 

Person with gloves wiping modern sink with cloth
The sink overflow hole is the part of the sink that prevents water from spilling out.


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How to Clean a Stinky Bathroom Sink Overflow Hole

Because it’s in a humid environment, and at a constant exposure to moisture, the bathroom sink overflow hole can grow mold and mildew that can emit musty odors from your bathroom. Organic material, such as food waste, and congealed oils from conditioners and lotions, can also cause foul odors that may emit from your sink. 

Just as you would any bathroom fixture, you would need to clean your overflow hole routinely to prevent odors from emitting from your sink. Make sure to scrub clean any reachable areas in and around the overflow to loosen the grime buildup, and get rid of mold colonies. To clean the overflow hole, you’ll need a few staple household items. 

You Will Need:
  • Distilled White Vinegar (not Apple Cider as this can leave stains on the sink)
  • Baking Soda
  • Boiling Water or Warm Water
  • Silicone or Metal Funnel (to withstand extreme temperatures)
  • Flexible Pipe Tube Brush or Drain Brush
To Clean The Overflow Hole:
  1. Use the silicone or metal funnel to pour 1 cup of baking soda into the overflow hole. Follow through with 1 cup of white vinegar, pouring slowly as the two ingredients make a fizzy reaction. 
    - This fizzy reaction contains acidic properties that lift dirt and grime from surfaces, making them easier to scrub out.
    - This solution also deodorizes your drainage system to get rid of any foul odors.
  1. Let the two ingredients sit for 15-20 minutes, use a pipe tube brush to scrub any parts of the sink overflow that you can reach.
  1. Pour in a steady stream of hot, boiling water. Skip this step if your sink is not made from ceramic, stone, or porcelain as the boiling water may warp and damage your sink.
  1. Repeat as needed to completely deodorize the sink overflow. 
  1. For plastic and resin sinks, allow the boiling water to cool just until warm before funneling into the sink overflow.
  1. If your sink has a cap or stopper, check the manufacturer’s instructions on how to properly remove the cap before starting. Make sure to brush the cap as well to fully clean it. 
    - Use the same baking soda and vinegar solution to brush away any mold growth on the stopper. Rinse well, and allow the cap to dry before replacing it back onto the overflow hole.
    - Do not rinse with boiling water if your stopper is made from plastic.
Helpful Tip: Sink drain cleaner brushes are commercially available, and specifically made to be flexible enough to clean drains and sink overflow. Having one in your home comes in handy for cleaning out grime buildup in drains.

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A Clean Sink is a Clean Bathroom

Unlike toilets, sinks seemingly require low maintenance, and almost no cleaning. However, a sink can get just as dirty as any other bathroom feature due to its frequent use, and constant exposure to moisture. While regular wiping down of the surface does well in general cleaning, we as homeowners should take extra care in the maintenance of our septic systems.

For a full top to bottom cleaning of your bathroom, sink, and drains, it is best to schedule with a professional for a routine cleaning schedule that will make your fixtures feel like new. 

We here at Luce Home offer services that go above and beyond the usual, and our trained part time maids in Singapore know how to properly clean every inch of your home. Contact us to schedule your appointment today.

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