Basements are often forgotten parts of our homes, but they play a crucial role in keeping them structurally sound and providing us with extra living space. Plus, they provide a bonus area to store all of the personal belongings that somehow tend to accumulate more and more over the years. While these spaces can be a great benefit in a home, they can start becoming a serious problem if they’re not properly maintained. Mold in a basement can turn your home into a massive health hazard.

And life is hard enough without having to deal with that fungus among us popping up!

So why is it that mold thrives in basements? The answer lies in the unique environment often found in these spaces. Basements are often damp, dark, and poorly ventilated, providing the ideal breeding ground for microbial growth. And when mold grows in a basement, it can easily spread throughout the rest of your home, contaminating the air and surfaces therein. This can lead to poor indoor air quality and a host of health problems.

In this blog, we'll explore the various factors that contribute to mold in a basement popping up and provide you with practical tips to help you prevent it from happening.

But First, What is Mold?

Did you know that mold is a type of fungus that's found all over the planet, with over 100,000 species identified so far? It's a rockstar in nature, playing a key role in processes such as decomposition. But when it shows up uninvited in places such as your basement, it's like a houseguest who's overstayed their welcome—not so helpful anymore.

When mold gets cozy in your home, it will start reproducing and releasing teeny-tiny particles called spores into the air. These microscopic particles float around like party favors, landing on any surface they come into contact with. The key thing to remember is that these spores are similar to the seeds of a plant—they're non-living until they land on a surface with the elements needed for growth. Thanks to their hardy nature, most species just need a couple of key ingredients to start growing.

These include:
  1. A food source
  2. A moisture source 

And if those two elements are present on a surface for just 24-48 hours, mold spores can start setting up shop and colonizing the area.

Now, when mold grows in nature, it's no big deal—those spores have the whole world to disperse through. But when it happens in your home, it's like setting off a confetti cannon that never stops. The tiny particles ride the air currents throughout your house, leading to a buildup of harmful particles. It's like a never-ending party, but one you definitely don't want to attend.

So, what can you do to keep mold from turning your basement into a non-stop mold fest? Stay tuned for more tips and tricks on how to kick mold to the curb and take back control of your basement!

What Causes Mold in a Basement? 

mold in a basement

The first step towards combating mold in a basement is to know what can cause it in the first place!

Here are some of the top routes mold in a basement occurs.
  • Poor ventilation: Basements are more airtight than other parts of your home, with fewer windows and doors. Without proper ventilation, humidity levels can increase, creating an ideal environment for mold to thrive.
  • Flooding: Unfortunately, no home is immune to flooding. Natural disasters, excessive rain, damaged pipes, and structural issues are a few of the common causes that can lead to a home experiencing severe water damage. And with this watery event comes a list of problems, one of which is increased indoor contamination.
  • Plumbing problems: Drains, faucets, and pipes for home systems are often located in the basement, making them more susceptible to water leakages and poor drainage systems. Keep an eye out for any signs of overflow or leaks.
  • Organic materials: Mold needs organic materials to grow, such as wood, paper, and fabrics. If your basement contains these materials, such as storage boxes or old furniture, it can provide a food source for mold to thrive.
  • Humidity: Everyday activities such as showering, cooking, and doing laundry can produce moisture and increase humidity levels in your home. Without proper ventilation, this can lead to mold growth.
  • Cracks in floors or walls: Even a small crack in your basement floor or walls could allow rainwater into your basement, providing a perfect habitat for mold growth. Promptly cleaning up any water and fixing the crack can prevent this from happening.
  • Faulty sump pump: A malfunctioning sump pump can lead to flooding, which can easily lead to mold. 

By being aware of these common culprits, you can take proactive measures to prevent mold growth in your basement.

Is Mold in a Basement Dangerous?

Indoor mold exposure is a serious threat to our health, yet it's often overlooked.

Many people believe that mold is everywhere, so it's no big deal when it's in the home. However, this is far from the truth. The greatest reason for concern is the differences in the volume of exposure. While we encounter mold particles outside, they have the entire world to disperse through so it’s a low-volume exposure. Mold indoors only has the interior of the building to disperse through. With little airflow and filtration measures, the indoor environment can quickly become contaminated with mold particles.

Standing in a contaminated indoor environment is not the same as being outside. When we're inside a home with mold growth, our immune system is constantly facing an army of particles with every breath we take. While our immune system can typically get rid of a few mold particles throughout the day, a contaminated home means that our immune system is facing a continuous and overwhelming battle.

One of the biggest points of confusion is that no two people react the same way to mold exposure. While some people's immune systems can fight off these foreign invaders, others may experience a long list of symptoms or related autoimmune conditions. Researchers are still working to determine how and to what extent mold exposure affects the body. Factors such as lifestyle, immune system status, genetics, species of mold, presence of toxins and bacteria, and volume of exposure all play a role.

It's important to note that anyone with a developing or compromised immune system is at greater risk of developing symptoms faster and to a greater extent. Mold exposure can lead to conditions like Aspergillosis, and it's crucial to take it seriously. By recognizing the dangers of indoor mold exposure, we can take the necessary steps to keep ourselves and our loved ones safe and healthy. Like preventing mold in a basement!

How to Prevent Mold in a Basement

Preventing a problem before it pops up can help you avoid unwanted exposures and save money from costly remediation projects. So it’s a win-win! Here are a few steps you can take to prevent mold in a basement from happening to you.

Check for structural problems 

One of the key components to preventing mold in a basement is preventing moisture from making its way indoors. The less moisture there is, the fewer opportunities there will be for mold growth. Ensuring the home's exterior is prepped to act as an appropriate barrier is a huge part of this push to avoid water intrusion. 

Routinely take a close look around your home to determine if there are any cracks, gaps, or other issues that could allow moisture inside. 

Places to check include:

  • Foundation 
  • Attic
  • Roof
  • Windowsills 
  • Door frames 
  • Siding 
  • Basement

If you find any problems, take care of them ASAP so moisture intrusion does not occur. The sooner you can catch and resolve the problem, the better so that mold in a basement is not a problem for you. 

Clean regularly 

preventing mold in a basement

Set up a routine cleaning schedule to ensure your home remains in tip-top shape. We can’t exactly put a bubble around our houses, so particles like mold spores and mycotoxins will inevitably blow inside. It’s up to us to actively work to keep particle levels low. Deep cleaning regularly helps remove particles like spores, bacteria, and toxins. This improves air quality and decreases the likelihood of microbial growth.

Building the right cleaning product arsenal is a key piece of the puzzle. You want to make sure that the tools in your toolkit are up to the task of actually removing microscopic particles from surfaces.

A few great options to get you started include:

Prioritize dusting

Microscopic particles settle where dust settles. Dusting can help reduce the number of particles that get kicked up into the air that proper air filtration must deal with. Make sure to use slightly damp microfiber cloths during this cleaning process, as they are 100 times better at wiping away small particles than regular rags, as well as a HEPA vacuum cleaner.

Minimize moisture

Reducing opportunities for microbial growth includes eliminating the components they need for growth. That means keeping moisture levels low! There are a few great ways to check off this task. Keep in mind that the sooner any water-related situation is addressed, the better.

Steps to minimize moisture include:
  • Fixing leaks ASAP
  • Keep up with appliances to make sure they don’t harbor water, malfunction, or leak
  • Clean up spills
  • Ensure windows and doors are sealed properly so humidity and precipitation don’t come inside

Store items properly 

One key way to avoid mold in a basement is by not storing porous materials in the space as much as possible. This includes clothing, cardboard boxes, home decor, and everything else in between. If these items become wet, they’ll become a perfect home for microbial growth. 

If you have to keep porous items in the basement, make sure to store them off the ground on stainless steel racks and in sterile containers. Anything stored in these spaces should be placed with ventilation in mind to allow airflow and avoid becoming wet from issues such as flooding. This is a huge part of the process in preventing mold in a basement.

Reduce clutter

preventing mold in a basement

Work to minimize the number of belongings that are in the home. The more personal items we have, the more surfaces there are for dust and microscopic particles like pollen to collect on, and the harder it is to properly clean a home. Every year, evaluate your belongings and ask yourself if you truly use each item before deciding whether to ultimately keep it or move on from it. Doing so will make future cleaning easier and more thorough, which ultimately translates to cleaner indoor air quality and improved wellness. Eliminating clutter also reduces the number of belongings that must be dried out if a water-damaging event occurs.

Keep gutters clean

Clogged and faulty gutters are one of the top problems that lead to moisture intrusion into a home and, as a result, mold growth. As basements are below ground level, these spaces are will be the first to experience water damage from moisture intrusion from the water-logged surrounding ground.

Cleaning them regularly during this watery season, ensuring that they’re installed properly, and directing them away from the foundation of the home helps prevent water from intruding inside and causing mayhem. Consider a downspout extension if there’s often heavy rainfall in your local area.

Maintain humidity

The ideal humidity level in a home should be between 35 and 50 percent. Too high or too low humidity indoors can cause not only wellness issues but also problems with the health of the home as well. 

When the humidity is too high, it can cause microbial growth, poor indoor air quality, and structural issues in the building. However, you also don’t want it to be too dry indoors! That can lead to adverse health reactions and structural issues like wood separation.

Ideal humidity should be maintained not only for comfort but also to maintain a safe indoor environment that promotes ongoing wellness. Check out this blog post for tips on safely lowering or raising your indoor humidity levels.

Pro tip: Use a hygrometer in these rooms to monitor humidity levels in real time and address issues as they pop up.

Avoid carpeting

Carpets can retain moisture, increasing the levels within your home. And where there’s moisture, there’s an opportunity for microbial growth. These types of surfaces are also more difficult to clean, allowing particles to build up and lower your indoor air quality. Avoiding this material is best to help steer clear of mold in a basement.

Test your dust

the dust test

Why dust? Gravity brings particles like mold spores, mycotoxins, and endotoxins down to horizontal surfaces like floors, doorframes, and furniture. So basically, where dust collects, so do these indoor contaminants.

Testing this dust once a year will help to determine exactly what’s hanging out in your home and alert you to any potential abnormalities. Highly contaminated dust is not only a health hazard, as all of those particles can enter the body when they’re kicked up into the air when the dust is disturbed. But it also indicates that there’s an underlying contamination problem somewhere in the home.

Make sure landscape grading is correct

Ensure that the landscape grading slopes down and away from the home in all directions. This helps divert water away from the home so that it doesn’t pool near the foundation. This can lead to issues like cracking that will allow mold into the basement.

Stay on top of HVAC maintenance

The HVAC is essentially the lungs of a home. As such, it’s important to ensure that it’s operating properly and not bogged down with issues like microbial growth. Condensation can build up within the ducts or the unit itself, which offers the perfect home for things like mold. This will then blow microscopic particles all throughout the home, contaminating the indoor space. Routinely scheduling a professional to come in and service the HVAC in the spring and fall before switching the unit can help avoid issues like mold in a basement developing.

Take steps to protect against flooding

Steps to prevent flooding may seem like a pain, but it’s absolutely worth the extra effort—even if you think that flooding could never happen to you. For those in a flood zone, it’s incredibly important to knock off as many steps as possible. Having a plan in place to properly handle any surprise or unavoidable flooding event is also key to maintaining a safe indoor environment.

Check out this blog for an in-depth look at how to protect your basement from flooding. 

Stay on top of windows

This includes making sure that any windows in the basement have good seals and that the tracks are kept clean. This will prevent moisture from creeping inside and help maintain the ideal humidity range of 35–50% to avoid mold growth. It also helps prevent pests from making their way inside and regulates indoor temperature. This helps avoid issues such as condensation when the different outdoor air meets the indoor air.

Keep up with window wells and venting

If your home has window wells or crawlspace venting, make sure they’re kept clean and free of debris. This will allow water to drain properly so it doesn’t build up and cause flooding in the basement. As you know by now, moisture situations like this can quickly lead to mold in a basement.

Upgrade filters

preventing mold in a basement

The most common way to determine the effectiveness of a filter is by using a grading system called MERV, or minimum efficiency reporting value. The higher the MERV rating, the more it will filter out and improve the air quality.

For the HVAC and dehumidifiers in the home, make sure to opt for the highest-rated MERV filter the unit can handle. This will help protect the machine from particles like mold spores getting inside and potentially growing. It will also help better filter out the air so that contaminants don’t just blow right back into the environment. That being said, check with the manufacturer to see which highest-rated filter the particular system can handle and then purchase that option. Otherwise, the airflow can be too restricted, which can result in harm to the system itself.

Keep air moving

When the air is warm enough, turn off the HVAC system and bust open those windows and doors to allow fresh air in. This will help replace the potentially particle-filled indoor air with fresh outdoor air. It will also help transfer air throughout the basement so that it doesn’t become stagnant.

After a couple of hours, close everything back up and jump into deep cleaning to remove any spores, bacteria, and mycotoxins hanging around. Make sure to blast your air purifier as well to eliminate any particles kicked up while cleaning and further help to prevent mold in a basement.

This being said, if the pollen count is incredibly high or if it’s raining, keep those windows and doors closed. This will decrease the number of particles coming inside and avoid high humidity indoors.

Make sure all condensation lines are clean

One important preventive measure to avoid mold growth is to keep all condensation lines clean. Condensation lines, which remove excess moisture from the HVAC and other appliances like a dehumidifier, are often overlooked and can become breeding grounds for mold if not properly maintained.

If these lines are not properly cleaned, they can become clogged with dirt, debris, and mold, leading to a number of issues. One common problem caused by a clogged condensation line is water damage to the surrounding area. As water backs up in the line, it can overflow the drain pan and leak into walls, ceilings, and floors, causing structural damage and leading to issues like mold in a basement.

Keeping them clean helps avoid this situation! The frequency of cleaning can depend on several factors, such as the level of humidity in the environment and the amount of use the system gets, so check with an expert for their advice.

Make sure any penetrations to the outside are sealed correctly

It’s important to ensure that any penetrations to the outside of the home are sealed correctly to prevent air and water from entering the home. This can cause structural damage and affect indoor air quality, so it’s definitely something we want to avoid. 

One of the most common types of penetrations in a home are vent pipes for plumbing and HVAC systems. These penetrations, if not properly sealed, can allow air leaks and moisture to enter the home, leading to issues such as mold in a basement and increased energy costs. Another example of a penetration that should be sealed correctly is exterior wire penetrations. By ensuring that penetrations to the outside of the home are sealed correctly, you can maintain a comfortable and healthy indoor environment while also reducing energy costs.

To check if penetrations to the outside of a home are sealed correctly, visually inspect the exterior walls and roof for any openings where pipes or wires enter the building envelope. These penetrations should be sealed with the appropriate materials, such as caulking. You can also use a smoke pencil or incense stick to check for any issues. If the smoke or incense is drawn into the home, it indicates that there is an area that needs to be sealed.

Invest in air purification 

air purification

It’s impossible to completely prevent particles from entering your home. Cleaning is a great way to remove them, but air purifiers also help to get rid of the rest of these particles. The fewer particles there are, the healthier your indoor environment will be, and the less chance of problems developing like mold in a basement.

Not all air purifiers are built the same, though. You want to go with a unit that removes the maximum number of contaminants possible and does it all of the time, not just some of the time. That way, they don’t recirculate back into the environment and potentially make their way into the bodies of those spending time inside. Air purifiers should at least meet HEPA status, meaning that they remove 99.97% of particles as small as 0.3 microns. If it can remove smaller particles, that’s even better. Some can also work to reduce other contaminants such as formaldehyde, VOCs, bacteria, viruses, and biotoxins. Also, pay attention to the space recommendations on the particular unit to ensure it’s equipped to filter the air for the size of the home.

A whole-home air purification system is the best option for success.

Check for insect intrusion 

Pests like termites and carpenter bees can introduce organic material into your basement that microbial growth can use as a food source. They can also allow pathways for moisture to intrude into the home, allowing for growth. Staying on top of sealings, fixing structural issues, reducing moisture, and cleaning often can help keep unwanted pests out and help avoid mold in a basement.

How Do You Know If There’s Mold in a Basement?

The sooner you catch a problem, the sooner you can begin to resolve it.

Take a Look Around

When it comes to finding mold in a basement, the first step is to do a visual inspection. Take a flashlight and examine every nook and cranny in the space. Look for any discoloration or abnormalities, keeping in mind that mold can come in all shapes, colors, and textures. Common colors include green, white, grey, blue, red, black, brown, or even pink. Textures can be fuzzy, powdery, velvety, or slimy. Don't forget to also look for signs of water damage such as dark stains on plywood, wet insulation, water spots on ceilings, and rusty nails.

Give it a Smell

mold odor

But what if you don't find any visible mold? That doesn't necessarily mean there isn't a problem. Mold could be hiding in a hidden location, like beneath insulation, or be too small to be seen yet. In this case, use your nose. Mold growth often creates a damp, musty, earthy smell due to the release of gases called microbial volatile organic compounds (MVOC). If you smell this in the space, there's a good chance you're dealing with mold in a basement because that is not just a normal “basement” odor!

Pay Attention To the Warning Signs

It's also important to pay attention to how you feel. Not all mold growth will be visible or create a smell. But our bodies have amazing warning systems that let us know when something is wrong. Have you developed chronic symptoms over time that no doctor can pinpoint a root cause for? Do they flare up anytime you go into the attic? If so, those invisible particles could be making their way inside your body and wreaking havoc. Always listen to your body when it says, "Hey, something is definitely not right here."

How to Get Rid of Mold in a Basement

When basement mold pops up, it needs to be taken care of properly and quickly. The longer it’s present, the more particles the colony will release into the air. 

Hiring a team of professionals to handle it is the best option. With all of the semi-porous and porous surfaces in the basement, it's an extensive process to remove the contamination. Mold grows roots, which can reach deep within these surfaces. These have to be removed so that the growth doesn’t pop right back up. 

First step: Hire a Qualified Mold Inspector

A qualified mold inspector should go through the entire home to determine if that's the only problematic area, figure out what led to the growth, and alert you to any contaminants present. 

The chosen individual should spend at least a few hours combing through the interior and exterior of the home using a variety of methodologies.

Some of the testing data you should expect to see is: 
  • Species of mold present
  • Quantities of each mold
  • Potential spore presence in the HVAC system 
  • Presence of mycotoxins 
  • Presence of bacteria

All of this information is needed to understand what’s actually existing in the home so that they can create the right protocol for the unique situation. If other contaminants, such as mycotoxins and bacteria, are present, the remediation protocol will need to address this. Should spores make their way into the HVAC, this will need to be remedied. Otherwise, those particles will blow all over the house and could turn into a new mold colony.

Second Step: Hire a Qualified Remediation Team 


With this information, a qualified remediation team can properly eliminate the contamination, ensuring that the home is safe for you and your family. Like mold inspectors, though, not all remediation teams are built the same. 

You want a company that prioritizes your health, understands the importance of creating a safe environment, and has proven success in remediating toxic homes. Their protocol should be built on three main pillars to ensure proper decontamination.

These three pillars are:
  1. Remediate the sources properly.
  2. Identify and address the problems that led to those sources in the first place.
  3. Eradicate all contamination created by those sources, including toxins and bacteria.

Failure to hit every point is an unsuccessful remediation.

If the source that led to the contamination isn’t addressed, the conditions for growth are still there, allowing the problem to come right back. Should the roots of the microbial growth be left behind, the colony can come right back. High levels of contaminants like mycotoxins and bacteria left behind can lead to continued exposure. Each scenario does not lead to a healthy home environment and can allow for any chronic symptoms to persist. 

Engineering controls should also be installed to ensure the contamination does not extend to other areas of the home.

The last thing anyone wants to do is waste money and time repeating the process while continuing to feel ill. The right team should check all of the above boxes so that when they leave, you can rest easy knowing that the mold on the bathroom ceiling is no longer an issue.

Afterward, give the basement and home a deep cleaning to remove microscopic particles even further. 

Here are kits that have the tools you need for success.

Trying It On Your Own?

diy remediation

If you want to attempt a remediation project yourself, proceed with caution and only work on areas under 10 square feet. Contacting an expert beforehand can give you a full breakdown of how to properly address the issue.

Things to keep in mind:
  • Use correct engineering controls and put PPE in place
  • The source that led to the growth needs to be resolved
  • All porous materials, like drywall, need to be removed and replaced
  • All surfaces need to be decontaminated using the proper remediation protocols based on the specific surface type
  • The surrounding space should be deeply cleaned to remove any particles released by the active growth

We offer various packages with the tools you’ll need to properly decontaminate your indoor space. 

Bye, Bye Mold in a Basement

Keeping mold at bay in your basement is all about staying vigilant and taking steps to eliminate the things that fungus among us needs to grow. With a little effort and attention, you can keep your basement dry, healthy, and mold-free! This will help you avoid potential horrors that can lurk in a damp basement and save money on costly remediation projects.

Plus, steps like this are a huge piece of the puzzle for creating a safe home environment that supports your ongoing wellness. A toxic basement can turn your home into an unsafe hazard zone. But fear not! Having greater awareness about the importance of improving your indoor space and maintaining healthy indoor air quality is a huge step towards bettering our well-being.

Still Have Questions?

A member of our team is here to help!  Click on “Get Started ➤” below to book a consultation with a member of the HOMECLEANSE team. We have a few quick questions that will help us put together a roadmap to solve or prevent all of your mold problems.

Two minutes of your time could lead to better health for you and your family.