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How to Identify and Fix Bathtub Overflow Drain Leaks

Bathtub overflow drains are essential components designed to prevent water from spilling over the sides of the bathtub, causing damage to your home.

However, when the overflow drain malfunctions, it can lead to significant water damage.

In this article, we will explore the causes of overflow drain leaks, how to identify them, and the steps to fix the issue.

Read on to learn how to deal with overflow drain leaks like a pro!

Water poured into the tub. Full bath.

Understanding Bathtub Overflow Drain Leaks

The overflow drain is a safety feature that prevents water from spilling over the tub’s edge by redirecting excess water back into the main drain pipe.

Despite its relatively small size and simple design, it plays a crucial role in maintaining your bathroom’s functionality and safety.

When the overflow drain malfunctions, it can result in water damage to the bathroom floor, the ceiling of the room below, and even the building’s structure.

Common Causes of Overflow Drain Leaks

Overflow drain leaks can result from a variety of issues, including:

  • Clogged Overflow Drain. Accumulated debris and soap scum can obstruct the drain over time.

  • Leaky Overflow Tube. Leaks in the overflow drain tube may seep outside the tub drain and through the bathroom floor.

  • Damaged Overflow Gasket. A cracked or deteriorated gasket can allow water to escape the overflow drain.

  • Leaving the Tub Running. A continuous flow of faucet water can overwhelm the drain and cause overflow.

  • Misdirected Shower Water. Overflow drain problems may occur when shower water consistently runs over the cover plate.

  • Deep Tub Soaks. Submerging the overflow plate during a deep bath can eventually compromise the drain’s capacity.

Identifying Overflow Drain Leaks

Follow these steps to find the source of your leak:

1. Fill the Bathtub

Fill your bathtub with water and observe if any water leaks from the sides or underneath the tub.

2. Turn off the Faucet

Turn off the faucet and closely inspect the areas where water seems to be coming from.

3. Check for Cracks

Look for any holes, cracks, or rust forming in the tub. This could be the source of the leak.

4. Inspect the Overflow Pipe

Remove the bathtub overflow cover plate and check the condition of the gasket. If it appears worn out, consider replacing it.

What You Will Need

Before diving into the step-by-step guide on fixing a bathtub overflow drain leak, it’s essential to gather the necessary tools, equipment, and materials.

Here’s a list of what you’ll need:

  • Screwdriver. A screwdriver is necessary for removing the overflow cover plate and reattaching it once the repairs are complete.

  • Needle-nose pliers. These pliers will help you remove the old gasket from the pipe flange and may also be useful in handling small components.

  • Utility knife. A utility knife can be used for cutting away old caulk around the overflow cover plate or trimming the new gasket if necessary.

  • Rubbing alcohol. This is helpful for cleaning the exposed flange and surrounding surfaces after removing the old gasket.

  • New overflow gasket. A replacement gasket is essential for fixing the leak. Be sure to purchase the correct size and type for your bathtub’s overflow drain.

  • Plumber’s faucet grease. This grease is used to lubricate the new gasket before installation, ensuring a better seal.

  • Caulk. Silicone caulk can be applied around the edge of the overflow cover plate to create an additional seal against water leakage.

  • Mop and bucket. Having a mop and bucket on hand is useful for cleaning up any water that may have leaked during the repair process.

Once you have gathered these tools, equipment, and materials, you can proceed with fixing a bathtub overflow drain leak based on my own tried-and-tested method.

Fixing a Bathtub Overflow Drain Leak: A Step-by-Step Guide

I first realized the importance of a properly functioning overflow drain when I discovered water damage on the ceiling of the room below my bathroom.

It turned out that my bathtub overflow drain had been malfunctioning for quite some time, and I hadn’t noticed it.

I followed the steps outlined below, and to my relief, I was able to fix the issue.

This step-by-step guide will walk you through the process of fixing the overflow drain leak, whether it’s caused by a clogged drain, a damaged gasket, or a cracked overflow tube.

1. Remove the Cover Plate

Unscrew and remove the cover plate, along with the overflow drain assembly. Inspect the components for signs of damage.

2. Inspect the Assembly and Gasket

Replace the entire assembly if parts are loose, clogged, or corroded. If the issue is a worn gasket, proceed to step 3.

3. Remove the Old Gasket

Gently remove the damaged overflow gasket from the pipe flange using needle-nose pliers and clean the exposed flange and surrounding surfaces with rubbing alcohol.

4. Insert a New Overflow Gasket

Lubricate the new gasket with plumber’s faucet grease, position it over the pipe flange with its thickest side on the bottom, and ease it around the opening in the overflow drain pipe.

5. Secure and Seal the Gasket

Work the gasket into place around the overflow assembly opening, ensuring it is secure against the flange for an even seal. Allow it to set for a few minutes.

6. Replace the Plate

Reattach the overflow cover plate, securing it with screws. Make sure it is tightly fastened to prevent water from seeping through any gaps.

7. Test the Overflow Drain

Fill the tub with water to test the newly replaced gasket and overflow drain. Check for any signs of leakage. If you still experience leaks, there might be other issues with your plumbing system that require professional attention.

8. Seal the Overflow Plate

Optionally, apply a bead of silicone caulk around the edge of the overflow cover plate to create an additional seal against water leakage. Allow the caulk to dry according to the manufacturer’s instructions before using the bathtub.

How to Fix a Leaking Bathtub Overflow Drain: Video Guide

Preventing Future Overflow Drain Leaks

After successfully fixing the bathtub overflow drain leak, it’s important to take preventative measures to minimize the risk of future issues.

Regular maintenance, including cleaning the overflow drain and inspecting the gasket for signs of wear, can help ensure its proper functioning.

Additionally, being mindful of potential causes of overflow drain problems, such as excessive water pressure or improper installation, can also help you avoid future leaks.

By taking these steps, you can protect your home from water damage, maintain a healthy living environment, and prolong the lifespan of your bathroom fixtures.

When to Call a Professional

While many homeowners can handle a moderate-level repair like fixing an overflow drain, it is essential to know when to call in a professional plumber.

If you have followed the steps above and still experience leaks, or if you encounter complications such as inaccessible plumbing or more severe damage, it’s best to contact a licensed plumber to diagnose and resolve the issue.


A leaking tub overflow drain can cause significant damage to your home if left unattended.

By understanding the common causes of overflow drain leaks, following a step-by-step troubleshooting process, and knowing when to call a professional plumber, you can prevent costly repairs and maintain the integrity of your bathtub and bathroom.

Kyle Tucker

Kyle from Kyle Tucker Plumbing is a certified plumber with over 20 years of professional experience installing plumbing fixtures such as bathtubs, sinks, and toilets, as well as installing gas lines and water pipes, performing bathroom repairs, and more.

Kyle knows how to deal with every plumbing issue that modern homeowners encounter, and he shares his lifelong experience with readers in an engaging and easy-to-digest way.

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