How to Know If Your Shower Pan Is Leaking

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You must never leave a leaky shower pan unchecked as it can damage your shower beyond repair with time. Not only will it lead to mold and mildew buildup but it can also damage the floors and ceilings of rooms adjacent to the bathroom.

In this article, we’ll discuss how to know if your shower pan is leaking along with the common signs and reasons for this problem. It’ll help you fix your shower pan timely to avoid expensive water damage.

How to Know If Your Shower Pan Is Leaking

The easiest and most effective way to check whether or not your shower pan is leaking is to perform a water test. You can use the steps listed below for this purpose.

  1. Seal your shower drain properly using a rubber plug to prevent drainage. You can also cover it using duct tape if you don’t have a rubber plug.
  2. Fill your shower pan with water to a depth of about one inch.
  3. Mark the water level using a marker. You can also place some pennies on top of one another so that they reach the top of the water level.
  4. Leave your shower pan with water for at least eight hours. Make sure that you close your bathroom door and windows to prevent ventilation. It’ll keep water from evaporating and help you measure changes in water level accurately.
  5. After that, return to the shower pan and inspect it for water level changes. If the water level is lower than the marked spot or top penny, there’s a leakage in the shower pan.

Common Signs of a Leaky Shower Pan

Other than the test mentioned above, the following signs will also help indicate if your shower pan is leaking.

Mold and Mildew Buildup

Mold and mildew buildup is one of the first and most common signs indicating that your shower pan is leaky. While this can be mitigated by by frequent cleaning of your shower pan, it won’t eradicate it if its leaking.

You’ll see black or green spots on the wall area around the shower pan. You can also inspect the shower pan seal for the buildup of mold and mildew.

If your shower is on the first floor, you will also see the same stains on the room’s ceiling beneath your bathroom. It usually happens when your shower pan has been leaking for some time and it might also have damaged the tile grouting.

Musty Smell

If you notice a musty smell right after entering your bathroom or shower, you might have a leaky shower pan. It’ll be similar to the smell that you experience in an old storage room or basement.

It happens when water gets accumulated underneath your shower pan and doesn’t evaporate and dry. Over time, the leaky shower pan can also lead to bathroom floor damage that will cost you a whole lot of money.

Water on Bathroom Floor

If you see water on the bathroom floor after taking a shower, consider it a red flag. It’s a clear indication that your shower pan is leaking and you need to get it fixed immediately.

Causes and Fixes of a Leaking Shower Pan

You’ll need to find the exact reason behind the problem to fix the leaking shower pan. Here’s a list of the most common reasons leading to a leaky shower, along with their solutions.

Cracked or Damaged Shower Pan

A cracked or damaged shower pan is one of the most common reasons behind a water leak. You’ll need to inspect your shower pan in such a situation for a crack or hole. A crack usually appears on the pan’s top border and the most common place for a hole is the pan’s inner walls.

How to Fix

To fix this problem, you’ll need to use a clean towel to dry the affected area properly. After that, you’ll need to apply silicone-based water-resistant caulking. Fill the crack or hole properly and let the caulking dry.

Most silicone-based caulking takes about one to two hours to dry but they need at least 24 hours to cure. So, you’ll need to make sure that you don’t use your shower for one day.

Damaged Shower Pan Seals

The sides of a shower pan along the walls are sealed with a water-resistant sealant. These seals can stay intact for a long period but they can also wear out over time.

It usually happens because of poor installation or when a low-quality seal is used. As a result, the water starts making its way underneath the shower pan and it can also reach the bathroom floor.

How to Fix

You’ll need to use a sharp knife to remove the damaged seal and clean its residue using a towel or microfiber cloth. Then, you’ll need to apply a high-quality mold and water-resistant sealant to fix the problem.

Important Note: Keep in mind that you won’t be able to identify this problem by using the water test. That’s because the water level won’t reach the seals. So, you’ll need to inspect the seals thoroughly to check if they’re damaged.


If your shower pan moves downward as you put weight on it, check the pan’s seals for damage. It happens when your shown pan isn’t mounted on the floor properly. When it moves down, it damages the pan’s seals and allows the water to start leaking.

How to Fix

While the reason for this shower pan leak problem is similar to the one mentioned above, you can’t solve it by resealing the pan. You’ll need to call a professional plumber who will remove the shower pan and reinstall it properly so that it doesn’t move downward due to weight.

Final Words

A leaky shower pan is never a good sign and you should make it stop leaking as soon as possible. Otherwise, it’ll start damaging not only your shower’s structure but also the ceilings and floors of adjacent rooms.

We hope this guide will help you understand how to know if your shower is leaking, along with the common signs, causes, and solutions to this problem.

Allen Michael is the Founder and Editor of Home Viable, a website that he started to provide readers with tips on home efficiency and automation. He draws on his engineering background combined with his family-of-four experiences for his articles.