18.01.2025

That’s what the second hole in the bathroom sink is for. It has an essential role.

By Lesia

The second hole in your bathroom sink, known as the overflow hole, serves an essential purpose in maintaining the functionality and safety of the sink. Here’s why it’s there and what it does:


The Role of the Overflow Hole

1. Prevents Overflowing

  • The overflow hole acts as a safety feature. If the water level rises too high—whether due to a clogged drain or leaving the tap on accidentally—the hole provides an alternative exit for water, preventing the sink from overflowing and causing water damage.

2. Aids Drainage

  • The overflow hole helps air enter the drainage system, which allows water to drain more efficiently. This reduces the chance of creating a vacuum that might slow down water flow.

3. Improves Hygiene

  • By reducing standing water, the overflow hole minimizes the risk of bacteria and mold buildup that can occur in stagnant water.

How It Works

  • The overflow hole connects to a channel inside the sink that leads directly to the drainpipe. When the water level reaches the hole, it flows through the channel and into the drain, bypassing the main bowl.

Maintenance Tips

  1. Clean Regularly: Debris, soap scum, and mold can accumulate in the overflow hole. Use a small brush or pipe cleaner to keep it clear.
  2. Check for Blockages: If water isn’t draining from the overflow hole, there may be a clog in the channel. Flush it with warm, soapy water or a vinegar solution.
  3. Inspect for Leaks: Ensure the connections between the overflow channel and the drain are secure, as leaks can cause hidden water damage.

Fun Fact

While it’s primarily functional, the overflow hole also plays a small aesthetic role by preventing watermarks and stains around the sink’s edges due to constant overflows.


This little feature in your sink is more than just a design quirk—it’s a crucial element for convenience and safety! 🚿