Why Is My Bath Waste Pipe Leaking?

There are certainly other things that can be more dangerous than a bath waste pipe leaking.

However, this situation is not to be ignored or avoided. Having your bathroom floor flooded is not only annoying but can cause additional damage over time.

Your bathroom tiles may rise, mold can appear, and other parts of the piping system will start to deteriorate. Before you know it, you’ll have way more than a bathtub drain to fix.

To help you locate and solve this problem, we wrote everything you need to know in this article. So, if you’re interested in fixing the leaking bath waste pipe, search no further!

Why Is My Bath Waste Pipe Leaking?


There are many possible causes of the bath waste pipe leaking onto your bathroom floor. Let’s quickly go over what may have caused the leak.

Keep in mind that these are only speculations based on the most common causes of this problem.

  • Rusted Pipes
  • Clogged Pipes
  • Deteriorated Bathtub Seal

Most bathtub waste pipe leaks are caused by deteriorating material over time. However, some of the causes have more to do with the force of impact or clogged items.

When pipes get rusted, the probability that they will burst is automatically higher. Multiple processes can result in pipe corrosion, from mild to severe. [1]

Pipes that are clogged can be under constant pressure and can flood your bathroom if not resolved on time. You should indeed avoid letting hair in your drain.

A deteriorated bathtub seal is probably the most common cause of bathtub leaks.

Below a bathtub, there’s a whole piping system that has multiple connection points. The leak can happen in any of these points if the pipe bursts or the joint weakens.

However, a bathtub flange is where the leak most likely happens, and it’s because of a faulty drain gasket. Let’s inspect this issue more closely and help you resolve it.

Why You Should Stop Bath Waste Pipe Leaking


You might think that reacting quickly to a problem like a bath waste pipe leaking is common knowledge – but it’s not!

Many people tend to avoid this problem, as they fear that the process of fixing it will cost a lot. It goes without saying, but postponing a problem doesn’t fix it.

Ignoring a bath waste pipe leak is easy as the flooding is not as visible as it is with other leakages. The water may seep into the bathroom floor or walls, creating more damage over time.

The added damage will take more time to fix and will almost certainly cost you more money. If you’re still not convinced to act immediately to fix this problem, consider other possible damages:

  • Foundation Shift – Bath or shower leaking behind the wall can cause the house foundation to shift, which is not safe at all.
  • Neighbors Complaining – If you have neighbors living on the floor beneath you, you can even face a lawsuit. This is for causing the damage due to a bath or shower leaking through the ceiling.
  • Mold – Water trapped inside the floors and walls creates a perfect environment for mold, fungi, and bacteria to develop and spread. Mold exposure can especially harm your health in many different ways. [2]

Locating The Leak


More often than not, you won’t notice bath waste pipe leaking that easily. People usually notice some puddles here or there at the beginning of this problem.

If you have children who like to play in the bathtub, this makes things even harder. Children have a habit of splashing the water whilst playing, so this can confuse you even further.

Sometimes, a bathtub leak can also get confused with condensation. After the bathtub gets filled with hot water, droplets can appear at the bathtub exterior because of the temperature change.

These droplets then collect onto the bathroom floor and create puddles easily. This also gets mistaken as a bath waste pipe leaking very easily. 

When locating a leak in your bathtub, you want to be more strategic in catching the leak. This will help you locate the leak and, therefore, the problem causing it.

What you want to do is follow the next few steps:

  • Insert the Drain Stopper Into the Bathtub Drain
  • Fill The Bathtub With Water
  • Check For Any Leaks 

By inserting the drain stopper, you stop the water from leaving the bathtub. Then, when you fill the bathtub with water, the water should stay in the bathtub.

If you notice any leaks, chances are you have a leak in your bathtub and not your bathtub waste pipe. Search for any hairline cracks – these are common in toilet bowls too.

Most probably, your only solution will be to replace the cracked bathtub altogether.

However, if there aren’t any leaks as of now, then you may raise the bathtub drain stopper. Assess the situation on the spot and pinpoint the source of the leak.

The leak should reveal itself, especially after you release a large quantity of water at once. Do this only with small leak problems – you don’t want to flood the neighbor’s ceiling.

Also, it’s useful to trace any signs of flood damage or water damage on the bathroom walls. Locating and fixing bathroom floor leaks is not always easy.

However, you can always search for any strange noises, risen tiles, and mold. Depending on the type of bathtub you have, the piping system might be visible or not.

When you notice a burst pipe or a leak from the bathtub seal, your next step is fixing that. If the piping system is not visible underneath your bathtub, it’s best to contact a professional to access the leak.

How To Stop Bath Waste Pipe Leaking?



If, after the close inspection of the piping underneath the bathtub, you find out the seal is leaking – you got lucky. The bathtub drain gasket leak is easily fixed.

The seal on the bathtub flange is made from the same putty used for a kitchen or a bathroom sink. It’s very common for this putty to wear out or loosen over time and leak water.

This is the type of leak that doesn’t require a professional to fix – all you need is to follow a few simple steps!

Sealing a bathtub drain is a fairly easy task, easily considered a DIY one. To complete it, you’re going to need:


  • Gloves
  • Caulking or Plumbers Putty
  • Bath Waste Seal Kit or a Sealant Caulking Tool Kit
  • A Flathead Screwdriver
  • A Smart Dumbbell Tub Drain Removal Tool

A bath sealant kits usually contain a grout scraper or a putty knife. This is necessary for removing the old putty or a sealant.

What you need to do to fix the leaking bath pipe is to remove the old seal and replace it with a new one. To do so, follow the next few steps:

  • Remove the Bathtub Drain Stopper

If you did the testing mentioned at the beginning, it’s time to remove the stopper to let the water out. Place the towels on the floor and a bucket underneath the bathtub to collect the water that may spill out.

If the bathtub is empty, you still want to remove any drain stoppers, as you will be working on the drain flange. Some bathtubs have a pop-up stopper inside the bathtub itself, so make sure you remove this one. You may need a flathead screwdriver for this.

  • Remove the Drain Flange

The next thing you want to do is remove the drain flange itself. A drain flange (or a drain basket) is a part of the drain visible from the bathtub.

For removing the drain flange, you’re going to need a smart dumbbell or a drain key. After inserting this tool into the drain, turn counterclockwise until the old drain can be removed.

A QUICK TIP: For the stubborn drain flanges – you can pour hot water over them or heat them with a hairdryer. This will help loosen the old putty and make removing the flange easier.

  • Scrape Off The Old Putty

After you remove the old bathtub drain, you will be able to see the residue of the old plumber’s putty. Your next step will be removing the old putty with a putty knife.

Make sure to properly scrape off any putty excess before you move on to the next step. Look in and around the drain opening to also remove any dirt coming up the drain.

  • Replacing The Bathtub Drain Gasket

A drain gasket that is sitting on the top of the drain boot should not be damaged.

Consider replacing the damaged gasket with a new one, as this is what contributed to the leak problem. An old gasket should be replaced with one of the equal models, so make sure to purchase the same one.

Otherwise, just reinstall or readjust the existing drain rubber gasket. You can do so by folding it and inserting it back into the drain opening with the help of a screwdriver.

  • Sealing Bathtub Drain 

After you clean the drain area and allow it to dry properly, you can move on to installing the drain flange. We recommend installing a completely new drain flange, even if the putty itself was at fault.

To install a new drain flange, you’re going to need a fresh plumber’s putty. Roll the plumber’s putty between your hands to create a snake-like shape.

Then, apply the putty around the lip of the drain flange. Make the putty-snake ends meet together, creating a circle underneath the flange lip.

Apply the drain flange with a plumber’s putty onto the drain opening, turning it clockwise. Make sure the flange is tight enough by tightening it with a smart dumbbell clockwise.

Remove any excess plumber’s putty with a clean cloth and a putty knife.

  • Reinstall the Drain Stopper

This applies only to bathtubs that have built-in drain stoppers as a part of the bathtub system. You may want to consider replacing a drain flange to improve a bathtub drain system.

If you only use separate rubber or metal drain stoppers, skip this step.

  • Test the New Flange 

There are two different ways for you to test the newly installed bathtub drain flange. First, you can run the water to see if there is any leaking around the drain flange.

If unsure, you can move on to the next part of the testing. Apply the drain stopper and fill the bathtub with water (not a lot of water is needed). If the water remains on the same level after some time, then you successfully reinstalled the drain flange!

Bath Waste Pipe Leaking After Flange Replacement

If you replaced the drain flange or even the whole bathtub, you could still deal with a bath waste pipe leaking. This is the case of a burst pipe, and the one requiring more tools, time on your hands, and also skills. [3]

In this case, we recommend that you contact a professional plumber to replace the part of the piping system. The professional plumber should assess the problem at hand and recommend the best possible solution for the burst pipes.

If not fixed, burst pipes can leak into your walls and cause further damage such as foundation shift, water stains, non flushable toilet waste and others.

Never hesitate to phone a professional when you don’t seem to fix the problem yourself. In particular, this is not a DIY project and requires more skills to prevent further problems.

The Bottom Line

The problem of bath waste pipe leaking can be caused either by a flawed bath gasket or a deteriorated putty. It’s very common for a plumber’s putty to need replacement after some time, and this is easily fixable.

However, make sure you first do some testing before replacing the drain flange and old putty. In some cases, it’s a cracked bathtub  or faucet that is leaking.

If the leak is not fixed with a replacement of the putty, gasket, and drain flange, then you should contact a professional. This is probably the case of a burst pipe, and it requires more time, skill, and more advanced tools.