Smelly Odor in Basement



Hover over the symptoms to discover how moisture & water can effect your home.



If you are reading this post, you are likely experiencing a musty, smelly odor in your basement. That unpleasant smell is concerning for many reasons. The smell itself is disturbing, but the underlying reason for the smell is the real concern. A smelly odor may be a sign of potential problems. In this blog, we explore some common causes of smelly odors in the basement and offer valuable suggestions about what to do about it.

Common Causes of Smelly Odors in the Basement

Musty smells in a basement are typically caused by moisture. Mold and mildew are common issues for homes with basements. Basements are naturally cooler than the rest of the home due to being entirely or partially underground. When moisture is present in a basement, mold and mildew growth risk increases. The moisture’s dampness and the basement’s darker atmosphere create an environment perfect for mold and mildew to thrive. Mold is a fungus that grows and reproduces by releasing spores into the air. The airborne spores are what cause the moldy, musty smell. However, dampness alone may also bring on a musty smell.

High Humidity

Humidity can occur anywhere. It is the measure of water vapor in the air. Typically a home’s humidity should be between 30 and 40 percent in the winter and between 50 and 60 percent in the summer. Basements are cooler than the rest of the house due to being embedded in the ground. A basement is a cool, dark space where condensation can accumulate, creating a damp, humid environment, often leading to mold, mildew, and other issues.

Water Leaks

Water leaks are a common issue for houses with basements. Common sources of basement water leaks include cracks in the foundation, failing window and door seals, or plumbing issues. Any water leaks in the basement may lead to mold growth. Dampness left behind from water leaks will leave a lingering musty smell.

Poor Ventilation

Basements are typically located underground, allowing limited access to airflow or natural light sources. In addition to the lack of natural ventilation, basements in older homes may have outdated ventilation systems preventing proper air circulation throughout the basement. Poor ventilation promotes the collection of moisture that can lead to a damp, musty smell.


On average, 98% of basements will have some type of water damage during the lifetime of the home. Common causes of basement floods include plumbing issues, surface and groundwater outside the home, and foundation cracks allowing water to seep through the flooring. Following a flood, an odor may linger long after removing the water from the basement.

Storing Damp Items

Even if no mold is present, storing damp things in the basement may cause an unpleasant odor. Damp items packed together are breeding grounds for different kinds of foul-smelling bacteria.

Standing Water in the Yard

Standing water in your yard is not just an issue for your landscaping. It may cause a musty, damp odor in your basement if it starts to seep inside. When water accumulates in the yard, it means it has nowhere to go. When the ground is saturated, water may penetrate your basement walls or flooring, seeping through any cracks or gaps, and resulting in smelly odors.

What to Do About the Odor?

Find the Source

It is crucial to identify where the smell in the basement originates. Finding the source will help you understand how it happened and what to do next.

Test for Mold

While a musty, foul odor does not always mean mold is present, it is safer to check. 70% of homes have mold present. Mold causes serious health risks to anyone living in or visiting your home. Finding out if you do or do not have mold in the basement will help you determine the best plan for the odor.

Repair Leaks

Find and repair leaks to prevent further damage to the basement. Inspecting your basement for visible signs of water and condensation on walls or pipes may help you identify the leak allowing you to repair it and stop water from continuing to enter the basement. Checking around window wells, drains, foundation walls, and floors for cracks and damage may also indicate the location of a leak.

Waterproof the Basement

After you find the source of the odor in your basement and fix the issue, waterproofing your basement is an excellent option to help prevent future water damage from excess humidity or water seeping in from the walls or basement flooring. Waterproofing can also reduce the risk of flooding, helps prevent mold growth, and reduces moisture collection.

Call a Professional

Some DIY methods can potentially eliminate basement odors however, it is often best to call a professional. Calling a professional can give you peace of mind about potential mold growth, removing mold if it is present, and ensuring your basement is repaired and sealed properly to prevent future problems with dampness, water, and humidity. Professional technicians have the training, tools, and expertise to identify the root cause and treat basement odor issues properly. If mold is present, professional service providers can handle the problem safely, minimizing health risks.

More about Basement Waterproofing

Whenever standing water or moisture is present in a basement, waterproofing is the best option to repair the issue and protect against further damage. There are a few different methods used for basement waterproofing. Choosing the right method for your basement will depend on several factors, including cost, durability, and choosing a temporary or permanent solution to the water issue that exists in your home.

Several common basement waterproofing methods are exterior waterproofing, interior sealants, and interior water drainage. Another more permanent solution is a basement panel system. Installing a basement panel system is a permanent solution offered only by highly skilled, trained professionals like Moisture Loc.

Moisture Loc

We are a family-owned and operated professional waterproofing and foundation repair company serving residential and commercial customers in Charlotte, NC, and the surrounding area. Our team of experienced, trusted professionals is ready to help you with effective solutions for basement waterproofing or discuss other services you may need for your home or commercial property. Request your free consultation today!

    Request A Free Consultation