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Best Way to Seal Overflow Holes in Drain? (Expert Guide)

Overflow holes in sinks keep your bathroom floor from flooding should the water level rises inside the sink. But you might sometimes need to seal the hole to collect water in the sink. Or, you might also want to seal the overflow hole permanently.

So, how to seal overflow holes in drain? You can seal an overflow hole in the drain by installing a rubber or silicone drain cover. Waterproof tape can be a good temporary solution for sealing overflow holes. And you can also use metal drain covers when the need is permanent.

Let’s discuss the steps of sealing overflow holes elaborately.

Tools and Materials

Depending on whether you are sealing the sink drain hole temporarily or permanently, you might require several tools and materials. Here is a list to choose from.

  • Rubber, silicone, or metal drain cover
  • Screwdriver
  • Sealant
  • Rubber Grommet
  • Metal Blind Bolt
  • Drilling Machine

Once you have all these collected, we can proceed to the main process of sealing the overflow hole in the drain.

How to Seal Overflow Holes in Drain?

How to Seal Overflow Holes in Drain

If you wish to seal a vessel sink drain without overflow temporarily, it will be different from sealing a sink or bathtub permanently. So, we will discuss them separately to keep things concise. Here comes the first category.

1. Sealing Overflow Holes in Drain Temporarily

There are two ways of sealing an overflow hole temporarily. Check them one after another.

a. Use Waterproof Tape

A roll of waterproof tape will be very affordable to seal the overflow hole. Follow the steps below to seal the sink.

  • Drain all the water from the sink and let it dry completely.
  • Once the surface is dry, look for any dirt or debris. If there is any, clean them properly.
  • After cleaning the sink, it’s time to apply the tape.
  • If the width of the tape is bigger than the hole diameter, applying a single piece should work. But if the tape is thinner, you should apply multiple strips to cover the hole completely.
  • For extra protection, you need to repeat the process from different angles.
  • Now, open the tap and try to fill up the sink with water to check whether the seal is okay. Remember, this seal isn’t that strong. So, any pointy object might pierce the seal.

b. Use Drain Cover

Another easy and effective way to seal holes in sink drain pipe is to use drain covers. These covers can be made of rubber, silicone, or plastic. Check the following steps to seal overflow holes with drain covers.

  • Choose a drain cover of the right size according to the diameter of the overflow hole.
  • Install the drain cover into the overflow hole. If the drain cover is made of rubber or silicone, you can easily install them. But if it is a metal drain cover, you might need to use rubber grommets. These small gaskets will keep the installation firm and noiseless.
  • Check whether the drain is properly sealed by running water into the sink.

2. Sealing Overflow Holes in Drain Permanently

If it is the kitchen sink overflow drain or bathtub overflow drain, you might want to seal it permanently. In that case, you need to follow the steps below.

  • Take a round metal plate larger than the overflow hole in diameter. You will also need some metal blind bolts to fix the metal plate.
  • Drill screw holes in the sink carefully. After attaching the metal plate to the overflow hole, apply a waterproof sealant to permanently seal the overflow hole in the drain.

How to Replace Bathtub Overflow Drain Gasket?

If there is a faulty gasket in your bathtub, you should replace it as soon as possible. The task will take only a few minutes with the right tools, so you don’t need to pay a costly visit to a plumber. Here are the steps.

  • First of all, take the old gasket out. You can use a small knife to scrape existing caulks.
  • Use a screwdriver to take out the screws on the overflow cover. You can use a knife or flathead screwdriver to pry open the cover.
  • Remove the old gasket and install the new one after lubricating.
  • If necessary, you can also replace the sink overflow cover.
  • Screw the cover back on and apply caulk around the cover. That’s all.

Is a Leaking Overflow Pipe an Emergency?

A leaking pipe might not be dangerous if we talk about kitchen sinks or bathtubs. The maximum they will do is fail to hold water in the sink or bathtub for your tasks.

But if there is any leak in the pop-up drain with an overflow that goes inside the cabinet beneath the sink, a leaking overflow pipe can be dangerous. If the leaking happens for too long, water can damage the necessary items stored inside the cabinet.

It can also damage the cabinet. So, you should be careful about a leaking overflow pipe, even if it’s not an emergency.

Things to Consider When Sealing Overflow Holes in Drain

Here are a few tips to keep your sealing work as neat as professional plumbers.

  • While using knives or sharp objects on sinks or other components, be careful not to scratch those items.
  • Whenever you remove any screws from sinks or drain pipes, keep them secured. Many people tend to lose screws once removed.
  • You should use a putty knife to spread the caulk evenly so that no gap remains beneath the caulk.


Though overflow drains are useful, they need to be sealed sometimes. Some people tend to call a plumber to handle this easy fix. But you don’t need that anymore. We showed several methods of sealing an overflow hole in the drain. Using these methods, you can easily seal overflow holes with the right material in a few minutes.

Perfectly sealing an overflow hole will help you increase the water level and keep things beneath the sink safe. Use the right tools and materials to get the job done with the least hassle.