10 Signs of Water Damage in Walls (or Ceilings)

By thewriteDuffy •  Updated: 06/07/24 •  7 min read

The worst-case scenario is when the water has penetrated the wall and you don’t know that it happened, giving dangerous mold and mildew time to grow. Even worse, prolonged moisture in your walls can also weaken the structural integrity of your home, making it susceptible to future problems.

Here are the 10 signs of water damage in your walls or ceilings you should never overlook:

1) A Randomly High Water Bill

If you see a dramatic increase in your water bill for no reason on month, a water leak can be the cause.

A good test is check if you’re using any water when you’re not using it.

To explain, your first step will be to record the water meter’s number. Next, make sure all sinks, faucets, appliances that use water, etc. are shut off, and leave the house for about three hours. 

When the three hours are up, come back and before anyone touches anything, record the number again. If the numbers are different by more than one or two, then you know you have a leak in the indoor plumbing.

If the number didn’t change, you’ll also have that test to reference when you contact your water provider and address the bill issue.

2) Water Sounds You Can’t Find the Source Of

No, you’re not going crazy. Sometimes a burst pipe, broken faucet, or a faulty appliance can actually be heard before it’s seen. If you hear something that sounds like water but can’t find it, put your ear to the wall and see if it amplifies.

If putting your ear to the wall makes it louder, it’s time to investigate.

A musty odor of mildew and mold is usually the first sign that something is amiss.

3) Softened Drywall

Softened drywall can be missed when the backside of the drywall becomes soaked, but the exterior appears normal for a while. 

Check for unseen wall water damage by pressing against areas of drywall you suspect could have water damage. If the wall buckles or becomes depressed, it’s wet inside and you have a water problem.

It is also likely that mold growth will be found since this type of wall water damage is often overlooked. 

4) Bubbling or Peeling Paint or Wallpaper

If your paint and/or wallpaper peels, bubbles, or otherwise loses adhesion, you definately have underlying water damage.

When water collects behind your paint and pools, it stretches the paint making a bubble. Finding this type of water damage is straightforward, but there’s no indication of how much wall water damage has occurred behind the scenes.

Small bubbles can be popped, but there will be a mess and there’s also a slight risk water will continue to flow through the hole, so have a bucket ready!

A large paint bubble being drained to minimize damage.

If you’re unlucky enough to find a huge water bubble, it’s best to call a professional at that point. Aside from having the right equipment and tools, they have the expertise to minimize collateral damage.

5) Cracking or Flaking Drywall

Heavily wet areas of drywall usually expand, and can cause cracks in the walls. If the inside of the wall is wet, then the drywall or paint can flake (or bubble as mentioned above).

If you see any cracking or flaking on your wall, it a solid sign of water damage.

6) Discoloration of the Walls or Ceiling

Water damage usually shows up as discolored drywall. Staining patterns showing through the wall (brownish or tan in appearance) can show up as circular stains or streaks running down the wall from the ceiling. These streaks can be short, a few inches long, or long, running all the way down.

Oftentimes, discoloration is coupled with softened drywall, so look for soft spots where the drywall is discolored. 

7) Warped Drywall

If your Sheetrock starts to bow or warp at the top and/or bottom that can be a sign of water damage (though it can also be caused by other problems.

If the cause is water, the warping is usually accompanied by staining, or softening drywall, so look carefully and feel the area for sponginess.

8) Wet Flooring or Carpet

If you’re floor or carpeting is mysteriously wet, the water can be coming from your walls.

Investigate by checking the walls in neighbouring rooms and the space above the wet floor for other signs of water damage.

9) Visible Mold or Mildew Growth

Mold begins in a home with small brown or black dots. 

Mold growth, especially if it’s the dreaded black mold, can be extremely detrimental to your health. On very rare occasions—when dealing with black mold—it can be life-threatening. You want that stuff out of your home as soon as possible.

You can remove mold yourself if the area is less than 10 square feet – just be careful! If you plan to remove the mold yourself, you should protect your skin and lungs by wearing gloves, safety glasses, a mask (at least an N95), and good ventilation.

This 10 square feet rule of thumb comes from the EPA, who also advises that if you choose to hire a company to do the removal, make sure the contractor has experience cleaning up mold. There are a number of guidelines a mold removal company should follow to remove the mold form you home safely. To learn more, check out the EPA site here.

10) Rainwater Comes into the Home

This one is dealing with a very specific leak, but a troubling one.

If it is raining and water appears to be coming in through the window, there could be a leak coming from the window, siding, or roof runoff.

Check the wall above the window and in any rooms above where rain is coming in for more water damage.

What to Do if You Find Water Damage in Your Wall or Ceiling

If you find any of these tell-all signs that there is moisture in the walls it’s time for action.

If the damage is extensive, you can opt to contact a professional water damage repair company and/or your insurance company.

If the damage is slight and you feel like you have the skills and wherewithall to tackle it on your own with some help from the internet, you’ll first want to find the source of the leak and then take steps to dry out and repair the damage. Here’s how:

How to Find Source of Water Leak in Your Wall

While some of the signs of water damage can be obvious, often the source is not.

Here’s a great video from Ron Hazelton showing how to use a moisture meter and some investigating to find the source of a leak:https://youtu.be/XEG6wl3htec The updated model of the moisture meter from General Tools is available on Amazon here.

Using a moisture detector can help avoid cutting a ton of investigation holes in your drywall if the source of the leak is unknown.

When to Contact a Professional

If you don’t have a moisture detector, your leak needs immediate attention, you have no idea of the cause, and the damage is great, it may be time to call a professional and save yourself the patchwork and mess of exploring the whole house with a drywall saw.

How to Dry Out and Repair Walls and Trim After Water Damage

After the leak is found, it’s time to address the leak and repair the damage.

Since there are an endless supply of possible causes of leaks, I won’t address each one here, but addressing the leak should be the priority.

Depending on the complexity of the leak fix, you may need to begin the process of drying out the damaged area(s) of your home before it’s completely remedied.

The steps for drying your walls after water damage and repairing your drywall can be found here. Following that list of steps (and it can help having a list during the chaos of a leak in your home) will help mitigate the damage and save any materials that can be reused after the leak is repaired.

If you also need to repair your MDF trim and/or crown molding you can find help with repairing water damaged MDF here.


At home, April is a mom, wife, and DIY darling. Among other home projects, she helped her husband Dan renovate their 1986 bungalow and is currently designing and decorating the 2023 custom home they are building themselves. Professionally, April is a writer, author, and online marketer with 15 years of experience writing for newspapers and magazines, building online authority websites, and publishing books.