The first step towards resolving an issue is figuring out if there’s a problem in the first place. When it comes to topics that society doesn’t touch on often, like mold, this seemingly simple task can be a bit tricky. How do you know if microbial growth has moved in? A solid understanding of the signs of mold in a home can ensure issues are caught quickly so that they can be corrected. 

Unfortunately, that fungus among us can be tricky. Obvious physical growth may seem like the easy answer, but it’s not the only indication of a contamination situation. There are several other signs that can all point to a problem. 

Keeping an eye out and regularly checking for any indicators is key to maintaining a safe indoor environment. The longer microbial growth is present, the more toxic the indoor space will become. 

Why Is Mold Indoors Bad News? 

Before getting into the signs of mold in a home, here’s why this should be a topic on your radar of concerns. 

As mold grows, it reproduces by creating microscopic spores and sending them into the surrounding space.¹’² Some species of mold can also create microscopic toxins called mycotoxins when threatened, further adding to the particle party.³ 

indoor air pollution

The longer a colony is thriving and surviving, the more particles will be blown all around. This isn’t a problem in nature because there’s a wide world to disperse through. Mold in a home is not the same scenario. Thanks to modern building techniques pushing for net-zero energy efficiency, there’s very little airflow between indoor and outdoor environments. That means that most of the microscopic particles produced by the mold, not to mention fragments from the colony itself, are trapped within the home's walls. 

This leads to:
  • Poor indoor air quality 
  • Contaminated surfaces all throughout the home (these particles can ride the indoor air current anywhere)
  • Increased likelihood of a colony opportunistically developing elsewhere in the home 

To add another layer of contamination problems, bacteria thrive in similar environments as mold.⁴ That means that where there’s mold growth, there are often bacteria as well. 

This situation can create a toxic indoor environment. As the average individual breathes 20,000 breaths per day and spends 90% of the time indoors, the state of our indoor spaces matters. Take a home with a current mold problem as an example. Every time the individual living in the house goes to sleep, sits down for dinner, turns on their favorite TV show, or hosts game night with friends, they're breathing in microscopic particles. 

Just because you can’t see them doesn’t mean that they’re not there. That’s one of the main dangers of indoor mold growth. It can be present and cause the air quality to plummet without anyone knowing. Over time, these particles will continue to build up in the home and the body and can cause all sorts of adverse health reactions. ⁵’⁶’⁷’⁸’⁹

Knowing the signs of mold in a home can help avoid this toxic situation and ensure our homes remain the safe havens we want them to be.

With that in mind, here are the top signs to look out for that could indicate a contamination situation.

Signs of Mold in Home #1: Visible Growth

signs of mold

This can be an easy box to check off to determine if your home is struggling with a contamination situation. The key is to know what to look out for.

With so many species existing in the world, mold colonies can come in a variety of colors, shapes, and textures. Some of the most common colors include green, pink, white, grey, blue, red, black, brown, or a combination of them. As for textures, they could be fuzzy, powdery, velvety, or slimy. 

A great idea is to grab a flashlight and comb through your home regularly to catch any visible signs of mold as soon as possible. 

Areas to pay close attention to include:
  • The attic
  • The basement 
  • Crawlspaces
  • Grout and caulk
  • Windowsills and doorframes
  • Appliances (coffee maker, dishwasher, refrigerator water spout, blender, laundry machine, etc.)
  • Exhaust vents
  • Showerheads
  • Sink faucets
  • Mattresses
  • House plants
  • Fireplace

Bonus Tip: One trick to help determine if there’s an indoor contamination situation is to check the toilet tank for mold or mildew. While the lid isn’t hermetically sealed, there’s very little air transfer between the inside and outside of the tank. A lucky spore could have found its way inside, but it’s far more likely that there were enough spores in the air from another mold colony in the home that one was able to opportunistically stumble across this wet oasis. You're much less likely to find mold in the toilet tank than in other damp areas like the bathtub caulking, so if there’s microbial growth inside this area, there’s probably a larger problem elsewhere in the home. 

Signs of Mold in Home #2: An Odor

signs of mold

If you don’t find any visible mold, that doesn’t mean that there isn’t a problem. The growth could be in a hidden location, like underneath flooring, or be too small to be seen by the naked eye yet.

In this case, rely on your nose. Mold growth often creates a damp, musty, earthy, cigar-like smell due to the release of gases called microbial volatile organic compounds (MVOC).¹⁰ If you smell this, there’s a good chance that you’re dealing with a contamination situation.

While looking for visible growth, use your nose as well to determine if there’s a smell that doesn’t quite belong in your home. Not only is it stinky, but it can be a sneaky sign of microbial growth.

Bonus tip: Pay attention to any odors that pop up when turning on the AC or heat for the first time as well. When the system flips from cool air to warm air, condensation can build up within the ducts or the unit itself, which offers the perfect home for things like mold. If a lucky spore lands in this moisture, it will begin to colonize the space, leaving you with hidden mold growth within the home. This growth will just continue to thrive undisturbed until those warmer or cooler months occur. When you flip the thermostat to the alternate setting (heat or cold), all of those moldy particles will be blown throughout your home and create a serious contamination problem. 

To avoid this, schedule an HVAC professional to service the machine twice a year before turning the system from heat to cool and vice versa.

Signs of Mold in Home #3: Water Damage

signs of mold

Mold thrives on surfaces where moisture is present. If you find signs of water damage in your home, there’s a good chance that microbial growth is present or is about to drop in and cause problems. Flooding events from appliances or heavy rains aren’t the only indicators of a problem, though. There are other, less obvious signs as well.

Here are some things to look out for.


Small leaks are one of the most common issues that allow for microbial growth in a home because they can go undiscovered for long periods of time. While looking for visible signs of mold in a home, keep an eye out for this type of watery event. 

Common places to look include:

  • Underneath sinks
  • Inside cabinets
  • Appliances
  • Attic
  • Basement
  • Around the toilet and shower
  • Hot water tanks

Bonus tip: Another great idea to determine if there’s a hidden leak is to assess your water usage and bill. If these are abnormally high, there could be an issue somewhere in your home. In that case, consider hiring an inspector to come in and assess the building. You can also set up leak detection devices to help monitor any hidden problems.

Visible Discoloration or Deterioration

Pooled water isn’t the only sign to pay attention to. There are other, less obvious indicators of water damage in a home. 

Things to look out for include:

  • Torn or degrading insulation 
  • Rusty nails
  • Discoloration/ coffee-like stains on the ceiling, walls, or carpet
  • Stains on wood
  • Frost buildup underneath the roof
  • Warping and/or sagging of flooring, wooden surfaces, door casings, windowsills, walls, and ceiling
  • Peeling and chipping paint or wallpaper

Signs of Mold in Home #4: Chronic Illness

signs of mold

Spores, mycotoxins, and fragments are small enough to be inhaled, absorbed, and ingested into the body.¹¹ Once inside, they trigger an immune response, which is the underlying factor in their ability to cause adverse health reactions. As the particles continue to enter the body, the immune system will attempt to keep up with removing them, but it can become overloaded or malfunction, particularly for those who are hypersensitive.

This opens the door for chronic symptoms or related conditions such as Chronic Fatigue Syndrome and Aspergillosis. 

That being said, common symptoms of exposure include:

  • Joint and muscle pain 
  • Cold and flu-like symptoms
  • Brain fog 
  • Skin issues
  • Chronic fatigue 
  • Mood swings 
  • Digestive problems 
  • Headaches 
  • Anxiety and/or depression 
  • Hair loss
  • Respiratory issues

The tricky thing is that no two people respond the same way to exposure. One person may develop seven symptoms while another has the occasional runny nose. If chronic symptoms develop, always consider environmental exposures as a possible culprit. Do not just accept them as the new normal. 

Our bodies are fantastic warning systems that will let us know when something is wrong. If you start feeling unwell, those invisible particles could be making their way inside of your body and wreaking havoc, causing your body to sound the alarm and say, “Hey, something is definitely not right here.”

Found One of the Signs Listed Above?

If you discover an indicator of microbial growth, it’s important to act quickly. If it’s a small problem that’s easily resolvable, like grout, tackle it using the correct remediation protocol and supplies. Check out this page for information on remediating different types of surfaces and appliances in a home. 

For larger issues, it’s best to contact professionals. 

Finding a Mold Inspector

mold inspector

The first step should be to hire a qualified mold inspector. This individual sets the foundation for success in properly handling a contamination situation. All of the data they collect will help create the comprehensive protocol needed by the remediation team to appropriately handle the problem. Not all mold inspectors are created equal, so make sure you choose the right person. 

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 home and could turn into a new mold colony.

For a list of qualified professionals, click here.

Hiring a Remediation Team

After the inspector comes in and collects data, your next step is to find a qualified remediation company like HomeCleanse to get rid of the mold on the bathroom ceiling. 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. 

three pillars

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. 

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.

Want to Try it On Your Own?

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

If you aren’t confident that you can tick off each box, the professional route is the way to ensure all the contamination is removed.

Not Sure if There is a Problem?

If you’re not quite sure if there’s a current contamination situation, use a tool like The Dust Test

the dust test

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 will help to determine exactly what’s hanging out in your home and potentially causing problems. 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. It also indicates that there’s an underlying contamination problem somewhere in the home. 

The Dust Test will help you know if there’s a problem before spending thousands of dollars trying to find one (both medically and in your home). And, if there is a problem, The Dust Test will indicate what you’re being exposed to before your inspector comes so that you can ensure they will find where it’s coming from.

Following the Signs

home health

Our homes play a huge role in our ongoing wellness. We spend an enormous amount of time in these spaces, so it makes sense! That’s why it’s important to actively work on ensuring it's a safe environment that supports our bodies. Having a contamination situation indoors throws a serious wrench in this health-conscious plan. 

Knowing the signs of mold in a home can protect our indoor environments from problems and keep them in tip-top shape. This is just another piece of the puzzle that is keeping our homes and families healthy.

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.


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