Skip to main content
Got a wet basement? Musty odors? Protect your home with our proven solutions & lifetime warranty.

A dry, healthy home starts here.
Contact your local dealer or call 1-800-638-7048

Find A Dealer Near You!

Signs of Basement Water Damage

Water poses a constant risk to your basement. You may occasionally notice damp basement walls or find a puddle of water on the floor. Worst case scenario, your basement may flood during periods of heavy rainfall or snowmelt.

Moisture or water problems in your basement can result in mold and mildew growth, rotted wood, or damage to stored possessions. Worse, basement water damage or mold can hide behind drywall, under flooring, or in other out-of-sight areas. 

The following are signs to look for when you think you may have water damage in your basement. If in doubt, Basement Systems has a network of locally-owned basement waterproofing contractors who can help.

Puddles or Standing Water

Water puddle on basement floor

Puddle of water on the basement floor.

The most obvious reason for water on the basement floor is a water leak from a shower, sink, toilet, washing machine, water heater, or a bad pipe. Water from outside that accumulates against the foundation can also find its way into the basement through cracks, joints, window wells, and porous concrete. Check for inside leaks first, then make sure the soil around the foundation slopes away from the house and that gutters and downspouts are working properly. A persistent water problem may require basement waterproofing with a drainage system to prevent standing water in the basement.

Damp Air & Musty Smells

Basements are notoriously damp and musty, but that doesn’t mean they should be. Damp, musty air in the basement is a sign of a basement moisture problem and mold growth. Water leaks, foundation cracks, gaps around windows, and malfunctioning sump pumps are common causes of high humidity, mold and mildew growth, and musty smells in the basement. Look for water stains on the walls or floor, condensation, drywall discoloration, or white mineral deposits; all signs that water is getting into the basement. Consider installing a sump pump and interior drainage system to prevent standing water that can result in moisture problems, mold, and musty smells.

Mold or Mildew

Black mold stains on a painted basement wall

Mold stains on the basement wall.

Basements are the perfect breeding ground for a mold or mildew problem. Mold and mildew growth occur when high humidity and organic materials are present. A musty smell in your home is a likely indication of water leaks, high humidity, or mold growth. You might notice mold stains on drywall, carpeting, furniture, or items stored in the basement. Keep an eye out for other signs of water intrusion, such as peeling paint, wall discoloration, or increased allergy symptoms. If your basement smells like cat urine and the problem isn’t caused by a cat living in the home, this could be an indication of a mold problem. Basement mold should be dealt with immediately and preventative measures should be taken to avoid negative affects to indoor air quality.

Cracks or Crumbling

Stained crack in a basement wall

A leaky crack in a basement wall.

Water can cause cracks in the foundation. Foundation cracks can allow water into the basement. When water accumulates against the foundation due to poor drainage, hydrostatic pressure forces the water through cracks and gaps in the foundation walls. When water seeps through a crack in the foundation, there’s an increased risk of mold and mildew growth. Foundation cracks should be sealed to keep out water and moisture, but it’s more important to divert water away from the foundation with proper drainage. While most basement cracks are nothing to worry about, horizontal wall cracks and bulging walls are typically caused by hydrostatic pressure and require professional foundation repair.


White efflorescence stain on basement wall

A white, chalky stain is left where the basement wall was wet or damp.

When water evaporates it leaves behind minerals, causing white, chalky stains called efflorescence, on concrete basement walls and floors. Efflorescence can occur wherever there’s excess moisture moving through the basement walls or floor. Common entry points include cracks, along the wall-floor joint, or through the porous concrete. Although there might not be obvious water leaks or puddles of water, the white stains are a common sign of water damage. Efflorescence isn’t harmful and can be easily cleaned, but the source of the water problem should be dealt with to keep the stains from coming back.

Flaking or Peeling Paint

Peeling basement wall paint

Paint peeling off a moist basement wall.

The most common cause of flaking or peeling paint on basement walls is excess moisture. Moisture causes the paint to lose adhesion. Rain, snowmelt, and groundwater leaks are the primary sources of moisture in the basement. Gutters and downspouts and landscaping that don’t divert water far enough away from the foundation are common causes of excess moisture in the soil around basement walls. Leaking or sweating pipes can also cause paint to peel.

Wood Rot

Rotted wood basement wall stud

Rotted wood framing behind basement drywall.

Moisture and high humidity are common problems in basements due to outside moisture, water intrusion, and interior sources of moisture. When water vapor or condensation form on wood surfaces, including ceiling joists, this can result in wood rot that may spread until it causes significant structural damage to the home. Bouncy or uneven floors over the basement can be a sign of a rotted or damaged floor joist or sill plate (wooden board that the joist sits on).

Sinking or Uneven Floor

Gap where basement wall meets floor

A gap where the basement wall and floor meet is a sign of foundation sinking.

A sinking or uneven concrete basement floor could be a sign of soil erosion or shrinkage under the foundation. Heavy rains can saturate the soil and cause water to pool under the foundation, which can result in structural problems. Check for signs of a sinking basement floor, including a gap where the basement walls meet the floor (cove joint or wall-floor joint), support beams that are pulling away from the ceiling, or cracks in the concrete floor. If the basement is finished and the concrete is covered by carpeting or finished flooring, it may be necessary to pull back the floor covering to check for cracks in the concrete. A sinking foundation should be inspected by a professional who can determine if foundation repair is needed.

Wet Drywall or Carpet

Wet basement drywall covered in mold stains

Mold grows on damp or wet drywall.

Basement water problems can make drywall and carpet wet. Plumbing leaks, water intrusion from outside, or condensation are all common causes of wet drywall and carpet in the basement. Some of the obvious signs of water damage to basement drywall and carpet are yellowish-brown stains, mold stains, and dampness. Unfortunately, it can be difficult to tell if there’s water damage below the surface. Check for bowing walls, drywall that’s pulling away from mounting screws, and soft spots in the drywall, which could indicate a basement leak or moisture problem.

Preventing Basement Water Damage

Have you noticed signs of water damage in your basement? Depending on the cause of your damp, musty, moldy, or wet basement, fixing and preventing basement water damage could be a do-it-yourself repair or it could require the help of a basement waterproofing expert. Learn more about how to stop water in the basement or schedule your free basement waterproofing estimate with your local Basement Systems contractor.

Basement waterproofing contractors find the source of basement water problems and design customized solutions to keep the basement dry, including installation of sump pumps, interior drainage systems, and replacement windows.

Looking for a price? Get a no cost, no obligation free estimate.

get a free estimate
Find Your Local Contractor

All products and services are provided exclusively by local contractors within the Basement Systems Network.

To ensure professional installation and superior service we carefully created an international network of over 350 trusted basement contractors.

Featured States: Alabama, Georgia, Kansas & Michigan

Find A Dealer Near You!

  • Or select a state or province to get started
  • USA
  • Canada
Find Local Dealer
Free Quote