• Jay G.

6 Warning Signs of Basement Water Problems

Updated: Jun 21, 2020

It's 2 in the morning and you are up to your ankles in water - inside your basement. While you use your shop-vac or buckets to get all the water out, you are also probably kicking yourself for not noticing that you had basement water problems in the first place.

Warning signs that your basement may have water damage include:

  • Water Stains on Basement Walls

  • Odors

  • Mold

  • Rusted Equipment

  • Bugs

  • Peeling Paint

In this article, we'll take a look at some of the warning signs of a wet basement and the steps you can take to mitigate your potential water damage issue.

1. Water Stains on Basement Walls

This may seem obvious, but if your basement walls are covered up with framing, insulation, and drywall, then you'll never see the stains.

Water stains on block foundation can come in a variety of colors and textures. The most common is white, blotchy stains called efflorescence. Salt compounds carried into your basement walls via water attach to the surface of your wall, leaving a shiny white residue.

water stains, waterproofing a basement, basement foundation walls, foundation walls, home basement repair
Water Stains - This Needs Fixing

Other stains can be reddish or dark. Red stains also indicate that water has penetrated your basement walls and that it is high in iron content.

Darker stains, or black growths, are either mold or water that is actively infiltrating your basement walls.

Over time, moisture left unchecked will mingle with the warm air of your house interior to create mold. Moisture plus air, even the cool air of a basement, will cause mold.

Regardless of the type of water stains you have, they all mean one thing: your basement walls are not dry.

What can I do? For starters, go outside your house and have a good look at your exterior foundation exactly where you found the water stains. Check the grade of the earth, the seals on any nearby basement windows, and the gutters above the leak.

If you still aren't sure what might be causing the leak, then check out our articles on how to waterproof a basement foundation because you may need a more serious basement drainage solution.

2. Musty Smell in the Basement

Smell something. in your basement that just smells...damp? Well, you probably have moisture somewhere down there where you don't want it.

Before you go digging up your foundation, first check your plumbing. Exposed pipes in a basement often sweat during the summer, as the cold water in the pipes meets the warmer interior air. Over time this sweat can create mildew on nearby framing, flooring, and drywall.

Install pipe insulation - either pipe wrap or foam pipe insulation - for an easy fix.

Also, check your basement windows. You might have some exterior caulking that has failed and is letting in moisture when it rains. Over time this runs down your interior walls and can damage your framing and flooring.

Check the exterior window caulking or install a window well and fill it with gravel to avoid pooling water right outside the window.

IF it isn't your windows or pipes, then you need to check your exterior basement walls for other leaks, because you have water somewhere.

What can I do? Check your insulation - make sure you have a vapor barrier between the insulation and your basement interior. If not, you will likely have some mold or mildew behind your drywall.

Be sure you have a powerful dehumidifier in your basement and aim for a humidity level at 50% or lower. Get one with a large pint capacity so you don't have to empty the reservoir as much.

3. Peeling Paint

Peeling paint on your block foundation walls can occur for any number of reasons. You could have simply used the wrong paint - or you used the right paint but didn't apply it properly.

If you are sure you used the right paint and applied it properly, then the surface may be getting damp, causing the paint to peel. If so, you need to thoroughly look over the wall to see where water might be getting in.

The good news is that if you've painted a basement wall, then you haven't put anything over it like framing or drywall. That means you can actually see where the potential problem might be.

What can I do? If you can't see an issue, go outside and look from the exterior. Chances are you need to adjust the grading - or crown - around your foundation in order to improve water run-off away from the house.

Check for cracks, holes, or other entry points. Look up and check your gutters. During a hard rain go outside and see if there is any pooling water near the problem area.

If all else fails, investigate what it would take to remove the peeling paint and paint over it with a different product. If there is no obvious water entry and the peeling is light, a new coat of waterproof masonry paint may do the trick.

4. Rusted Equipment and Appliances

Maybe you've noticed your furnace or heat water heater getting a little rust - or more than little rust - around the edges or sides. Why? You know that metal and moisture are not friends. When both are present, rust occurs.

If you have rusty appliances in your basement, it might be nothing. After all, a furnace room can be prone to moisture, particularly if you have a sump pit in there. If not, then you might want to investigate what is causing that rust.

Before you tear down your walls, make sure your hot water heater and plumbing aren't leaking or sweating. If so, install insulation around both.

An uninsulated hot water heater and furnace can increase the heat in your furnace room, which will in turn cause any cold water exposed plumbing to sweat - or condensate - more. This will cause rust on said appliances.

If you don't have sweaty pipes, check the walls. As mentioned above, thoroughly inspect your interior and exterior foundation walls for cracks and holes.

What can I do? After looking at your walls, check your exterior foundation for the usual signs of a basement leak. Fix gutters and slope earth away from your house.

Lastly, sand the rust off with low grit sandpaper and paint over it with a rust-inhibiting paint.

If the rust doesn't come back, then the problem solved. If so, then you've got to do more serious waterproofing of your basement walls.

5. Mold

Mold is a sure sign that you've got water problems in your basement. The problem with mold is that sometimes it easy to ignore - here's why.

mold in basement, mold, basement, leaky basement, moldy basement, water seepage, seeping water, leaky basement water, mold leaks in basement
This is Mold - A Basement's Greatest Enemy

Let's say you go into your storage room in your basement.

You move some bins around and you pick up a box. You notice that the wall behind the box has a bunch of black spots on it like this picture...

It's easy to ignore that if nothing else seems awry in your basement - no smell or dank air.

What can I do? The mold had to get there from somewhere - don't ignore it!

Look around your ceiling or in the corners of your basement walls. See if you can see other signs of mold. Remember, mold loves dark places. Look under other boxes and see if you can narrow down the source of the moisture.

If there is just a little bit on your floor or walls, it can be removed with a bleach solution and scrub brush. Peel back the insulation or drywall. Lots of mold means you have a bigger problem that might require a professional mold remediator.

6. Bugs

If you've noticed that the corners of your basement have begun to accumulate more than the usual amount of dead pill bugs or earwigs lately, then chances are there might be water in your basement.

A number of nasty bugs love to be near water, particularly cockroaches. If you are seeing more than the occasional roach in your basement, there may be a reason. Roaches and other critters love water - you often see them in bathrooms as well.

The bad part about having bugs in your basement beside the bugs themselves is that it is hard to tell where exactly your water problem is located.

What can I do? Check your floors for dampness and peel back a bit of your carpet or subfloor, if possible. Also, check behind your basement walls for stained block walls or mold.

As for the bugs, get a pest service and a dehumidifier. Keep your basement clean and locate the water source as soon as possible - once the water is gone, the bugs won't have much of a reason to visit your basement anymore.


Before you go ahead and dig up your foundation for serious waterproofing, remember that the issues mentioned above are often solved with simple solutions.

Check your pipes and basement windows for leaks. Fix your exterior landscaping. Check your gutters and downspouts to avoid pooling water. 90% of the time you'll find that the simple fix worked.

But familiarize yourself with the warning signs. If you ignore musty odors or peeling paint for too long, it might be too late for a simple fix. Be proactive and pay attention to your basement interior.

As always thanks for taking the time to read this article. Please leave comments or feedback below about how we can make this article more helpful for you!


We are 3 guys trying to help people save money.

Too often, homeowners throw up their hands and call a contractor.

Don't do that. Come to our site first - you can fix your basement with a little knowledge and a few tools.


Let us help you - contact us today!

  • Twitter
  • Pinterest
  • Facebook
Subscribe Now!

Alright Alright Alright