Do Bathroom Sinks Always Need An Overflow?


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Bathroom sinks overflow

The overflow is one of the most common features found in a bathroom sink. Look at the backside of your bathroom basin, and you will usually find a small hole there. The overflow can also be found in bathtubs and is a component that offers a couple of convenient functionalities. Now, is the overflow a mandatory feature in the bathroom sink that you should consider? 

In general, an overflow is unnecessary for most bathroom sinks. Also, the overflow is not fool-proof, and you still can’t leave the faucet running. Think of overflows as an additional component that does prevent overflowing but is not a mandatory feature. Vessel sinks are a good example that not all sinks require an overflow.

Do Vessel Sinks Have Overflow?

No, vessel sinks do not feature an overflow due to their core design. A vessel basin will typically feature a round sink installed atop the countertop. As such, there is no space to include the overflow opening. 

Do Undermount Sinks Have Overflow?

Bathroom interior with white sink and faucet

Yes, undermount sinks do feature an overflow. You can choose between models that have this feature and those that do not. As discussed above, an overflow is not an essential aspect of the basin, and you can do without this feature. 

The bathroom sink overflow is not mandatory as it is primarily an optional feature. So, what are the advantages of having a bathroom basin with an overflow implemented into its design?

What Does Bathroom Sink Overflows Do?

There are two significant functionalities that an overflow provides for both the bathroom sink and bathtub: 

  • Prevents overflowing
  • Faster draining

The sink overflow is a small hole connected to the drain, located on the upper part of the sink’s backside. It is usually positioned near the top and acts as a limit as to how high water can rise in the sink. In addition, the overflow allows air into the plumbing system, which improves the overall speed of the basin’s drainage capability. 

How to Clean the Bathroom Sink Overflow?

A downside that comes with having a sink with overflow is that it will also require cleaning. In addition, an overflow with debris buildup will be a significant detriment as it will lose its primary functionality. Over time, gunk will also accumulate near the bottom of the overflow chamber, significantly reducing its drainage capability. 

To ensure that the sink overflow will be able to maintain its functionality, you will also need to clean it manually from time to time. Here are several ways to clean the bathroom sink overflow:

Using a Liquid Cleaner

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Green Gobbler GGDIS2CH32 Dissolve Liquid Hair & Grease Opener/Drain Cleaner/Toilet Clog Remover (Image: Amazon)

This method is best applied regularly as a means to prevent blockage in the overflow’s drainage system. You can use a simple DIY liquid cleaner formula that uses a 50/50 mixture of water and bleach. 

Once mixed thoroughly, pour the mixture down the overflow hole via a water sprout or funnel. Let it sit for about 10 minutes and rinse by pouring in plain water. 

Manual Flushing via Rubber Hose

Drain King 340 All In One Easy to Use Drain Unclogging Kit, 1.5 To 3 Inch
Drain King 340 All In One Easy to Use Drain Unclogging Kit, 1.5 To 3 Inch (Image: Amazon)

We recommend using a 7/8-inch dishwasher rubber hose for best results, but any sturdy hose that can fit into the overflow hole will do. This method also applies if the overflow has a blockage. 

To remove the grime buildup inside the overflow, fill the sink with water and have it go slightly above the opening to let water flow into the chamber. Next, put the hose through the hole and blow it into it several times. You will likely feel some resistance when blowing air into the hose. 

Drain the sink and blow air into the hose again to check if the resistance is still there. If it is, repeat until you clear the clog. 

Unclogging Using a Zip Tie

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Antilog Plastic Lock, 100Pcs Plastic Disposable Zip Ties Self-Locking Tie Suitcase Shoes Bag Label Tag(Red) (Image: Amazon)

Any long plastic strip will do, but a zip tie works best. Get along zip tie, longer than the depth of your sink, if possible. Push the zip tie in the opening of the overflow and steadily work your way down. Once you hit the clogged drain, steadily push and shake the zip tie around to loosen the blockage. Pour some water into the overflow to help clear the drain as you move the zip tie up and down.