5 Easy Ways To Fix A Dry Basement That Smells Musty

So, your basement is dry but still smells musty. That damp, earthy odor isn’t just unpleasant – it’s a sign that moisture is somewhere, even if you don’t see it.

Musty smells in basements are almost always caused by mold, mildew, or poor air circulation. Left unchecked, this can lead to bigger problems like indoor air quality issues and even structural damage over time.

The good news? You can fix it. Here are five effective solutions to get rid of that musty smell once and for all.

1. Find the hidden moisture & fix it

Even if your basement looks dry, if there’s a musty smell, moisture is present.

Damp air, minor leaks, and condensation can all lead to that musty basement smell. But luckily, there's a way to track down the source. Here's how.

Foggy windows are a clear sign of excess humidity in your basement, which could be the reason for that musty smell.

1. Check walls and floors for damp spots, condensation, or white, chalky residue (this is called efflorescence – read this blog to find out all about that).
2. Inspect your foundation for cracks. Even small ones can let moisture in.
3. Look at your basement windows. If they’re fogging up, you have excess humidity.
4. Check behind furniture or stored items. Trapped moisture can lead to mold growth.

How to fix the moisture:

1. If you find cracks, seal them.
2. If condensation is an issue, insulate pipes and walls to prevent damp air from forming moisture.
3. If you suspect high humidity, move on to step #2. 

2. Lower humidity with a dehumidifier

Even if you don’t have a water leak, too much moisture in the air can make your basement smell musty.

Basements are naturally damp because they’re underground, where humidity levels are higher. If the air has nowhere to go, it lingers... which creates the perfect conditions for mold, mildew, and the smell you’re smelling.

We strive to keep our blogs informative and unbiased, but when it comes to dehumidifiers, the SaniDry Sedona is one of the best... and we proudly install it.

A dehumidifier is one of the best ways to fix this. Dehumidifiers remove excess moisture from the air. Even if you don’t have a leaky or wet basement, humidity in a basement tends to be higher than the rest of your house – especially if there’s poor ventilation or moisture seeping in through walls and floors.

When humidity levels rise above 50%, it creates the perfect environment for mold, mildew, and dust mites – the very things responsible for that damp, musty smell. A dehumidifier works by pulling in humid air, removing the moisture, and releasing drier, fresher air back into the room.

How to use a dehumidifier effectively: 

1. Choose the right size for your basement. Not all dehumidifiers are built the same. A small, store-bought unit may work for a closet or small room, but a basement needs something more powerful. If your basement is over 1,500 square feet, you need a high-capacity dehumidifier.
2. Set the humidity level to 50% or lower. The sweet spot for indoor humidity is between 45% and 50%. Anything higher risks mold, and anything lower can cause the air to become too dry.
3. Keep it running 24/7 until the musty smell is gone. A common mistake homeowners make is turning off the dehumidifier too soon. If your basement has been musty for a while, it takes time to fully dry out the air and remove residual moisture from walls, furniture, and flooring. For best results, run your dehumidifier for at least a week until the air feels dry and fresh.
4. Empty the water tank or use a drain hose. Dehumidifiers pull water out of the air, and that moisture needs to go somewhere. Most units have a built-in water tank that fills up over time. If your dehumidifier has a tank, you’ll need to empty it regularly – sometimes multiple times a day if your basement is very humid. If you don’t want to deal with that, look for a model with a built-in drainage system that can be connected to a floor drain or sump pump. 

Expect results in just a few days. Once you set up your dehumidifier, you should notice a difference quickly. Within 24-48 hours, the air should start to feel drier and the musty smell will begin to fade.

3. Keep fresh air moving

Basements often trap stale, humid air because they don't have the same airflow as the rest of the house. If air isn't moving, moisture builds up, and so do odors.

How to get air circulating in your basement: 

Ah... the trusty box fan. No home feels complete without one.

1. Use fans strategically. Point box fans toward problem areas to keep air moving.
2. Open windows (if possible). If outdoor humidity is low, letting in fresh air can make a huge difference.
3. Install an exhaust fan. If your basement has a bathroom or laundry room, venting the damp air outside helps prevent moisture buildup.
4. Keep basement doors open. This allows air from the upper floors to mix with the basement air, reducing that stagnant feeling.

If your basement still smells musty after doing these steps, it might mean mold or mildew is already growing.

4. Deep clean to kill mold, mildew, and odor sources

Musty smells don't just exist on their own. They come from mold spores, dust, and damp materials that trap odors. Even if you can't see mold, microscopic spores can still stink up your basement.

How to clean a musty basement:

Time to throw on the gloves. It’s basement-cleaning time.

1. Scrub walls and floors with a mold-killing solution. Use a mixture of one part bleach to ten parts water or a commercial mold remover.
2. Clean carpets, rugs, and upholstery. If they smell musty, wash them with vinegar and baking soda, or consider replacing them.
3. Wipe down surfaces. Bookshelves, storage bins, and even holiday decorations can absorb musty smells. Give everything a good clean.
4. Use baking soda or activated charcoal. Place bowls around the basement to absorb lingering orders. 

Once your basement is clean, don't skip the next step. Cleaning won't matter if the musty smell keeps coming back.

5. Waterproof your basement for long-term control

If musty smells are a recurring issue, your basement might be taking in moisture from outside. Even if you fix the immediate smell, it will return unless you solve the root problem.

Waterproofing solutions to try:

1. Improve your exterior drainage. Keep gutters clean, extend downspouts away from your foundation, and make sure your landscaping slopes away from your house.
2. Consider an interior drainage system. If your basement has chronic moisture issues, installing a perimeter drain and sump pump can keep it permanently dry.
3. Apply a waterproofing barrier. Adding a vapor barrier to your basement walls can help block moisture from coming in.

If you've tried everything, call an expert

It's there...Moisture "lurking" in your basement. Find it before it finds you.

A dry basement that smells musty isn't just annoying... it's a sign that moisture is lurking somewhere. If you ignore it, you risk mold growing, air quality issues, and damage to your home.

If you've tried everything and the smell keeps coming back, it's time to call an expert. 

We didn't introduce ourselves earlier, but we're Thrasher Foundation Repair, a foundation and basement contractor with 50 years of experience. When it comes to basements, we know what to do. If you are in our service area, we're here to help with any basement questions, humidity issues, or dehumidifiers. You can reach out by calluing us at 1-800-827-0702, filling out the form below, or starting a chat in the bottom right-hand corner.

Additional resources for you

If you found this article helpful, there's plenty more where that came from. Our extensive library is packed with information about basements. Below are a few recommended reads, but feel free to explore our entire library for more insights. 

1. 5 Effective Tips To Reduce Humidity In Your Basement
2. What's That White Stuff On My Basement Walls?
3. What Is A French Drain? Different Types, How It Works, & Benefits
4. The Reason Why Your Basement Is Humid 
5. Why Your Basement Leaks & 5 Easy Ways To Fix It