Why Is There a Musty Smell in My Basement?

If you notice a sweet and slightly musty smell in your basement, it is very likely that you have issues with dampness (and probably mold). The underlying cause of this dampness, however, could be found in many different areas.

Internal Sources

Internal sources of dampness include plumbing leaks and appliance breakdown, as well as failures in your foundation’s drainage systems. The size of the internal leak can vary widely, too. Plumbing leaks, for example, can be incredibly small, like those that occur when the joint between two pipes is weak, or very severe, like when a pipe bursts. Of course, larger leaks are easy to spot quickly, while small leaks may seem less destructive at first, but can cause more damage over time because they remain undetected.

Likewise, appliance breakdown can cause increased humidity and dampness in your property, while producing very little visible moisture or water. A sump pump that is draining slowly, for example, may never cause flooding (if you are lucky), but it could allow water to stand in your property for long enough to impact the relative humidity inside. Likewise, a slight leak in your water heater could produce very little standing water, but a lot of condensation.

External Sources

External water sources are those sources that let moisture into your home from outside the property, either as a result of damage or design oversight. Seepage, for example, is an external source of moisture that sees water seep through concrete walls or floors because of the porous nature of concrete as a material. Leaking window wells can also let water into your home.

Leaking window wells can be caused by many different things and can take a number of forms. It can range from a barely-there seep of water that is only noticeable because of staining to a full-on trickle of water that forms puddles on the floor during a heavy storm. Once this happens, you will need to address the leak formally (which is why it is best to prevent damage in the first place, where possible).