Leak Under Bathroom Floor – What To Do?

The problem of leaks under the bathroom floor can be tough to solve. There are many resources online to help but, do they have all the information? Luckily, we've researched the problem and have the answers that you need right here. 

The first step you need to do is solve what type of leak you are dealing with. There are certain types of leaks you should look for: 

  • Grout and caulk leak
  • Drain leak
  • Shower splash leak
  • Toilet flange leak

After you've identified which leak you are dealing with, you have to consider your options. Some are easy to fix on your own, while other leaks may need a professional hand. Regardless of the path you take, each leak will need replacement of parts or reapplying sealant. You will also need to assess the amount of damage the leak has done and plan your steps accordingly. 

Now that you know the steps to take, you may wonder how you can prevent leaks from occurring. The damages water can have in your home can be devastating. You want to make sure leaks do not happen again to avoid any financial or structural suffering. To know all this and more, keep reading ahead. 

Water leaking on the bathroom floor, Leak Under Bathroom Floor - What To Do?

Signs of a Leak

You may have noticed some water leakage on the bathroom floor but, are leakages always this obvious? No, there are other signs you may have damage inside the home that you can easily overlook. 


Have you noticed a musty smell? If there's an odor that lingers even after you have cleaned the bathroom thoroughly, you may have some unseen mold growth. If there's leakage on the floor, the chances are that you may also have some water damage on the inside walls. 

Wobbly Toilet

How about the toilet seat? Are you experiencing some lopsidedness? If the toilet does not stay still, even if you try hard enough, there might be a toilet flange leak. A toilet flange leak occurs when there is damage to the wax seal. The wax seal is in charge of keeping the area airtight to prevent water and sewage gas from leaking. 

Loose Flooring Tiles

Lastly, how severe is the damage to the floor? Since water leaks can often go unseen, you should take minor signs like loose tiles seriously. If you notice tiles are not staying in place, then you have water seeping somewhere. Another sign of water damage can also be crystal clear. If your floor is starting to look worse for wear, you may be overlooking a leak. Vinyl flooring will begin to curl provided there's enough water for it to occur. 

How to Fix A Leak

To solve the problem, we must tackle it step by step. You first have to identify where the leak is happening. That may seem obvious but, you need to know how to identify them correctly. Here are a few types of leaks and some techniques to repair them.

Splash Leaks

This type of leak is one of the minor ones that you may overlook. It's one of the most common leaks that can lead to extensive damage if not addressed quickly. If water is constantly meeting the floor, it will eventually seep into the subfloor. The water will cause wood to rot. It will cost a hefty fee for repairs.

To test for splash leaks, splash water around the shower door and frame. After five minutes or longer, water might seep around the area. If you have a shower curtain, however, splash water around the curtains. Once signs of leaks occur, there are a few DIY steps you can take to fix them. 

For shower doors, you should rub and fill any gaps with a small bead of caulk. Once it dries, test for leaks again. Shower curtains, on the other hand, should be replaced when worn out. Make sure the curtains surround the entire bathtub. If you are looking to replace your shower door, we also offer some advice in that area by clicking here

Toilet Flange Leak

Toilet flange leaks are a topic we covered above. They occur because of damage to the wax seal. Another reason they happen is that there is damage to the flange. The bolts holding the flange will show some wear. Check for cracks in the slots where the bolts are. To fix it, you will need to replace the wax seal. If the flange has broken, you will need to install a metal repair flange. 

To know this is the type of leak you are dealing with, here are some key signs. For upper stair bathrooms, stains will appear on the ceiling below. In the case of bathrooms located on a ground level, water will have shown up on the base of the toilet. 

Drain Leak

A plumber installing a bathtub drain

A drain leak is one of the toughest problems to spot. It occurs in the area of the drain fitting. The piping of the drain might become loose over time. Since this leak happens under the bathtub, you might have already faced heavy damages to your floor. Signs of a drain leak include discoloration in the ceiling and bathtub sagging due to damages to the subfloor. 

The fix for this type of leak may require some professional help. One method to fix a drain leak is by replacing the drain fitting. This process is a complex one. Some DIYer's may be able to pull it off. Otherwise, you should seek professional services. You do not want to make a problem worse by not knowing what you are doing. 

Grout and Caulk Leak

A tile setter putting grout using a caulking gun between tiles for water protection

This last leak is another one that is easy to overlook. Most people do not miss it intentionally because who checks their grout and caulk? It would not cross a person's mind, but worn-out caulks and grouts are a significant issue. Splashing a bit of water on the floor might not seem like a big concern. However, if grout lines between the bathroom tiles have cracks, water can seep through and damage the subfloor. 

A repair man using a caulking gun

Similarly, caulk is used to seal the seams between the top of the tub and the wall. If this area has cracks, water might be entering the wall. Once water enters the wall, it can go further down to the floors, causing rotting, mold, and a musty smell. 

To avoid or fix this problem, you should routinely check grout lines on the tiles and caulk lines around the tub. If you find any signs of wear, reapply grout or caulk to the area. 

Now that you know how to spot leaks, you may be wondering, can you hire a professional to fix it? What about damages? What can you do to decrease the amount repairs are going to cost? 

Does homeowners' insurance cover plumbing water damage?

Water can cause a lot of damage. How it happens is what matters to insurance companies. You may be able to work your case, but most insurance policies have a set of rules they follow. 

Insurance companies will cover water damage from leaky plumbing if it is sudden and accidental. An example of a sudden and unexpected leak would be a burst pipe. If a leak happens due to poor maintenance, they will not cover the costs. 

Failing to repair a leak would fall into the category of poor maintenance. For more information on water damage coverage, you can consult with your own insurance company to see what your policy offers. 

When should I replace my subfloor from water damage?

A bathroom under construction with different equipment's laid on the unfinished floor

There are some tell-tale signs that your subfloor might need to be replaced. They are:

  • The floor is squeaking
  • Tiles are cracking or popping out of place
  • Floorboards are cupping
  • Some areas of the floor are sinking

If you experience any of the above, it is time to get your subfloor checked and replaced. However, if leaks are not the source of damage, you may want to replace your bathroom flooring. For more information on that, you can click here

Do plumbers fix leaks?

We know it is less costly if you fix a leak on your own but, getting professional help should always be welcome. Plumbers will fix leaks, and it is probably in your best interest to look for their assistance. For piping issues, you should likely seek professional help.

DIY solutions are sometimes a temporary fix to a big problem. Spotting crucial signs might be out of your field of knowledge. The cost of a plumber visit will not cost as much as potential unspotted water damages. 

Final Thoughts

Catching the leaks ahead of time can help you avoid unsustainable damage to your home. The signs of a leak may be obvious but knowing what to do after is also crucial. Although some leaks may have DIY solutions, you should also consider if you need a professional's opinion. Hopefully, you have found the answers you are looking for. Until next time!

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