Routine home cleaning and deeper spring cleaning help keep your home looking its best, but more important is that they benefit your health. Mold is a reality in homes. It leads to allergies and more severe health issues for all who live there, and it affects your family and future owners, which can also influence your resale value. Left untreated, mold can be a significant and big and expensive job to remove.
The good news is that some simple inspections and cleaning strategies will help everyone breathe easier.
We cover the topic of mold extensively, and this article lays out everything you need to know about mold. We discuss what it is, the types of molds commonly found in homes, and how to prevent mold from growing inside your home.
The Top 10 Mold Stats and Facts of 2023
- The most common indoor molds are Cladosporium, Penicillium, and Aspergillus. 1
- 70% of U.S. homes have mold growing in them. 1
- Texas and Florida are two worst states for mold growth. 2
- At least 45 million U.S. buildings contain unhealthy mold levels. 3
- Keeping humidity levels below 50% can help prevent mold growth. 1
- Dampness is estimated to be present in 20% to -50% of U.S. households. 4
- Every year, there are 6.7 million premature deaths because of household air pollution. 5
- 93% of the world’s children under the age of 15 breathe in polluted air every day. 6
- Mold growth starts within 24-48 hours of flooding or water damage. 7
- People with asthma and other respiratory breathing problems are more sensitive to mold. 1
What Is Mold?
Mold is a natural fungal growth that thrives anywhere moisture and oxygen are present. It eats virtually any organic matter. If you see it, the mold is living off whatever it is on. It looks a bit like a stain and ranges in color — white, pink, dark green, brown, or black.
Mold spreads by releasing spores that work like seeds of a plant. Spores travel by air or water and attach to clothing or fur. When they land inside the home, they remain dormant without humidity but reproduce and grow in damp, wet, and humid areas. When mold grows large enough, we can see it.
7 Types of Mold
There are seven types of molds, each of which has specific features and locations of growth, and ways to avoid them. To help you understand each mold better, here are five terms often used to describe mold:
- Allergenic: causes allergic reactions
- Toxigenic: produces a toxin or toxic effects
- Carcinogenic: has the potential to cause cancer
- Pathogenic: capable of causing diseases
- Teratogenic: causes developmental deformations in human fetuses
This mold has dark brown or green hairs and a velvet-like texture. It grows on carpets, wallpaper, windows, HVACs, bathrooms, and any damp areas. It is prevalent in areas with water damage.
This mold spreads fast, so immediate removal is the best action.
This toxigenic mold is commonly known as black mold and is either black or dark green. It grows in areas with high humidity, such as laundry areas, basements, crawlspaces, bathrooms, wet carpets, and on wood and cardboard products.
The best way to avoid this mold is to keep the humidity below 50%.
This mold is allergenic, toxigenic, and carcinogenic. There are more than 185 species of it in a broad range of textures and colors. It shows up as thick walls of mold and is common throughout American homes. It thrives in damp areas such as walls and surfaces. It often enters homes through windows during construction or earth moving and growing in compost piles and dead leaves.
You can avoid this mold by using HEPA filters and closing your windows during times of construction.
This allergenic mold has either a pink or black color. It is usually found on grout and caulk in bathrooms and kitchens. It can sit on painted walls when the moisture level exceeds 75%. It even grows on wood furniture and under wallpaper when moisture is nearby.
To prevent this mold from building, maintain airflow in the room to ensure that moisture doesn’t remain over long periods.
This mold is allergenic, pathogenic, and it’s also believed to be carcinogenic. It has a texture like cotton and has a musty odor. It also changes color: it starts off white and then progresses to gray, brown, and black. It’s found in areas of profound water damage, such as along roofs, attics, and basements.
You can combat this mold by reducing excessive moisture wherever it takes place and regularly watching for water damage.
This common allergenic mold has a velvet-like texture and a blue or green look. It grows anywhere moisture is present, particularly in areas with water damage. It goes airborne easily and can infest new areas of homes in just a few weeks.
Because Penicillium spreads easily, to keep it away, removing it and staying vigilant about preventing condensation and water leaks wherever spores take root is crucial.
This allergenic mold has a pink, red, or white color. It grows in soil and can spread indoors when attached to wet areas of the home, even in cold areas of the country.
Though this mold originates in soil, fungicides don’t kill it easily. Remove it from your home immediately and follow the preventative procedures listed below to keep it from spreading.
Common Places Where Mold Grows
An easy way to prevent buildup of any of the seven molds is to check the typical mold-growing areas of your home. Not all mold is noticeable initially. It could be behind walls or ceilings. But follow any musty or foul smells to track it down.
Mold collects quickly in showers and bathtubs, especially those that aren’t well-ventilated. Check the grout and caulking, and inspect around the shower head and faucet, shampoo bottles, shower curtains, washcloths, and loofahs.
You can usually find mold around the sink and toilet. Check the counter faucet, the top counter, storage areas underneath the sink, plumbing, and any toothpaste and toothbrush holders.
Check behind and inside the toilet tank, on the floor around the toilet, and look at areas where you store cleaning supplies. Don’t forget to inspect any carpeting inside or outside the bathroom.
Food is a significant contributor to mold growth, particularly old food. Check for mold inside the fridge and in cabinets. Refrigerator drip trays and water trays near water dispensers are also common mold areas. Look inside microwaves, behind the stove, on cutting board surfaces, and inside trash cans. Even dirty dishes and garbage disposals create mold.
As in bathrooms, check underneath the kitchen sink and around the under-counter plumbing for leaks or water accumulation.
The sink, plumbin, and laundry appliances often foster mold growth. Look for water and condensation in and around the machines, pipes, faucets, and counters.
Mold also grows when wet clothing sits inside washers and dryers for prolonged periods. Poor venting worsens the problem. Front-loading washers are more of a concern than top-loading washers. If you have a front-loading washer, check the door for mold.
Issues can occur in any room of your home, even if there’s no reason for water to be there. But the living room is a place with windows, vents, wallpaper, painted walls, carpeting, wood furniture, and fabric on furniture and drapery. Note any musty smells or discolorations. Don’t forget to check around any plants and neighboring surfaces.
Lastly, check the chimney. Masonry can spread mold quickly.
You can follow the same steps as those for your living room. One addition here is the mattress. Many bed designs don’t allow mattresses to breathe well, which leads them to attract moisture, especially in warm months. Check the mattress carefully for any discolorations or musty odors.
Attic, Basement, and Garage
Attics, basements and garages can get humid in hot and cold weather and are often dark, all of which are prime conditions for mold growth.
The attic is one of the most common places for mold because it’s close to the roof and doesn’t get inspected regularly. Mold enters homes through the ventilation system and shows up along the rooflines, in insulation, inside vents, and near the water furnace.
For basements, look around pipes and ductwork for moisture or leaks. Check the foundation and any water-related products like water heaters and pumps.
In your garage, check the bottoms of walls and any areas near water, such as your water heater, laundry sink pipes, and around and under the sink.
Other Areas of the Home
For a look at other common spots where mold can hide, click here.
Dangers and Effects of Mold
Mold affects the air quality in your home. If it builds up, it can be worse than dust or smoke. Side effects from exposure include coughing, sneezing, and asthma, but you may experience other symptoms depending on the type of mold. Here are common issues found with each of the seven types of mold:
- Alternaria: Can cause allergies, asthma, and a range of pulmonary diseases.
- Stachybotrys: Causes fatigue, headaches, breathing issues, and irritation of the skin and eyes.
- Aspergillus: Causes allergic reactions that worsen lung issues. Some versions create a dangerous carcinogen called aflatoxin.
- Aureobasidium: Causes hay fever, hypersensitivity pneumonitis, and asthma. When touched, it can create dermatitis and lead to rashes.
- Chaetomium: may cause hay fever, sinus issues, and asthma. It is believed to be carcinogenic and teratogenic.
- Penicillium: Can cause lung inflammation or hay fever.
- Fusarium: Causes allergic reactions as well as brain abscess/infection, which can be life-threatening.
What to Wear When Entering an Area With Mold
Before inspecting your home, collecting samples, and cleaning, wear protective clothing. Be cautious if you’re prone to allergies or breathing problems or if you take medications that reduce your immune system. Keep children away from inspection areas. Keep windows and doors open during inspections.
Items to wear:
- Goggles or eye protection
- N-95 respirator or one that provides even more protection
- Long-sleeved shirt
- Protective gloves
- Long pants
- Waterproof boots
How to Test For Mold
Here are steps to test for mold at home. Note: if mold exceeds 10 square feet, the U.S. Environmental Protection Agency recommends using a professional company for cleanup.
Step 1: Perform a Visual Inspection
Start by referencing our “Common Places Where Mold Grows” section above. Take note of any discolorations in each area and of any musty smells. Because some mold is not visible, odors are worth investigating.
Step 2: Get a Test Kit
You can purchase test kits through Amazon or most hardware stores. They aren’t expensive, usually costing less than $10. Many kits let you analyze results yourself, or you can send results out for professional analysis for an added cost.
Step 3: Collect Mold Sample
Collect samples using the type of gathering method your kit offers. A typical list of options:
- Swab samples: Run the swab over the mold, dip it into a solution inside the petri dish, and close it. Some kits may have you place the swab into a protective tube and ship it off for analysis.
- Tape samples: Tape samples are effective, but you’ll need a flat area to take samples. Remove the adhesive and place each tape against the mold. Then put the tape back into its protective case and follow the instructions for processing (i.e., petri dish or shipping).
- Open petri dish samples: You can place the solution inside the dish and put the dish in an area for a limited amount of time, such as one hour, and then close the dish. For example, if you test your HVAC, you can place the dish inside the vent and run the air conditioner so that air blows over it.
- Bulk samples: Cut and remove the discolored area (for instance, a portion of the wall surface or piece of cardboard) and place it in a protective plastic bag for shipment to a laboratory in your area.
Step 4: Monitor Petri Dish
Mold can take two to three days to show up but is easy to spot if it’s present. The liquid solution is mostly transparent. Any round colored spots are proof of mold.
Step 5: Send Sample for Identification
Your kit should come with detailed instructions for sending mold samples. If it doesn’t, you can send it to a mold laboratory in your area. Complete the company’s Chain of Custody (COC) form so the facility has the information they need to provide results.
Cleaning Tips for Getting Rid of Mold in Your Home
If a moldy area in your home is less than nine square feet (3 feet by 3 feet), you can clean up the mold yourself. If the area is larger, the EPA recommends hiring a professional service.
Before you start, there are some important factors to note:
- Be sure to avoid mixing bleach with ammonia or any other cleanser when cleaning.
- Open windows and doors when using any cleaning products.
Here are recommended ways you can clean out the mold:
Products That Kill Mold
In bathrooms and kitchens, you can use any cleaning product designed to remove mold. (Tilex is a popular brand.) You can also make your own blend and opt for more natural ingredients, though natural solutions may take longer to work and may not remove all stains.
A Solution that Uses Bleach
Add a blend of one part bleach and three parts water to a spray bottle and spritz the area. Wait 10-15 minutes and then scrub away the mold. Repeat the process until it is gone. Then mix a solution of 50% white vinegar and 50% hydrogen peroxide, which removes mold and its roots. Spray the area and let it dry.
A Natural Solution Without Bleach:
- Hydrogen peroxide: Pour 3% hydrogen peroxide into a spray bottle and spray the moldy area. Then wait 10 minutes and scrub away the mold.
- Vinegar: Pour undiluted vinegar into a spray bottle and spray the mold. Wait one hour and clean off the mold with water.
Here are ways to clean up mold throughout the home.
Removing Mold in Bathrooms
Once you have sprayed the area with your desired cleaning spray, scrub the mold off grout, caulk, and hard surfaces such as window sills and tile with detergent and water. Then dry completely with a rag.
To learn how to clean window screens, click here.
Removing Mold from Wood
Mold will sink deep into wood because wood is an excellent food source. Start by vacuuming the wood with a HEPA vacuum and dislodging sections of the mold with a soft brush. (Wear a mask.) Then add a teaspoon of dish soap to two cups of water in a spray bottle and spray on and around the mold. Wet a paper towel and wipe to remove excess liquid.
Follow this process by mixing a solution of one tablespoon of borax with one cup of water and applying it with a brush, letting the solution soak into the wood. If mold is still showing, sand the wood with sandpaper. If the wood is still stained, it is most likely mildew.
Removing Mold from Windows and Doors
If you have wood windows and doors, follow the steps from above. But if they’re painted, cleaning is easier. Wipe the wood with a damp paper towel and remove more challenging sections with a soft brush. Spray a solution of one teaspoon of dish soap and two cups of water on the wood and scrub the area again. Then wipe with a paper towel.
With these steps complete, lightly spray a solution of one part white vinegar and 3% hydrogen peroxide over the area and let it air dry.
Removing Mold from Drywall
This one is tricky because overly wet or soft drywall is often ruined. The best solution is to cut out the affected area and replace it with new drywall. You can also brush off the mold as best you can and spray the 50/50 hydrogen peroxide and vinegar solution and wait 10 minutes. Brush the area with a medium-bristle brush in circular movements; then dry it with disinfectant wipes and let the wall air dry. Repaint with mold-resistant paint if desired.
Removing Mold from Fabric
If you can use bleach on the material, do it; otherwise, you can use white vinegar. Place the vinegar on a cotton pad and lay the pad on the mold for 5 minutes before doing a regular sofa cleaning or laundering the fabric.
How to Prevent Mold
Now that you have removed the mold, you can follow some practical steps to keep it from returning. Mold prevention helps keep the mold from starting in the first place, saving you significant time and the cost of removing it. Preventative practices are relatively easy once you make it a routine. Here are some tricks to follow.
Monitor Humidity Levels
Humidity is a key contributing factor for mold growth. Check humidity levels with your thermostat and adjust them using your HVAC system or dehumidifier.
Clean Up Water Spills and Keep House Dry
This step includes drying wet doors and windows and related window frames. If you spot any water leaks, fix them immediately because they boost mold growth significantly.
Look for Areas With Water Damage
Mold thrives near water damage because the issue isn’t spotted immediately. Look for any damage in all areas of your home, especially in the basement and attic.
Improve Air Flow in the House
It may seem counterproductive to open windows because mold can enter a home through them. But stagnant air is another way to contribute to mold growth because it prohibits evaporation. Look for ways to keep the air flowing.
Use Vents and Fans in the Kitchen and Bathroom
Use a fan for 30 minutes after showering or bathing. Use a fan, vent, or open window while cooking and washing dishes.
Keep Your Kitchen Clean
Clean your countertops, cabinets, refrigerator, oven, stovetop, and microwave regularly. Wipe up any wet areas immediately. Remove trash daily.
Regularly Inspect for Leaks
Check faucets, pipes, and wet spots on walls and ceilings that may point to hidden leaks.
Make Adjustments to Your Bed
Consider a mold-resistant mattress, a waterproof mattress cover, and a slatted frame to help the mattress breathe and stay cool and dry.
Make Sure Fabric is Clean and Dry
Sofas and beds are two areas where people spend a lot of time. You can prevent mold created from sweat by regularly cleaning the fabric and drying them after washing. You also prolong the beauty and life of your sofa along the way.
Monitor Hidden Areas of the Home
For attics, check for leaks and wet spots along the roof, insulation, and inside any vents that lead to humid areas, such as bathrooms and kitchens.
For basements, look near water heaters and furnaces. Repair leaks as soon as you see them while ensuring outdoor venting. Waterproof the wall surfaces outside of your basement.
Carpeting is another hidden area of the home for mold, and you may not even see or smell it. You should regularly inspect high-risk areas by peeking under a corner and have the mold professionally removed.
Don’t Forget to Monitor Your Plants
Check indoor plants to ensure they aren’t overwatered. If they create overly humid areas, consider waterproof or water-resistant paints.
Keep Laundry Areas Dry
In laundry areas, keep wet clothing from sitting over long periods. Keep the washer and dryer doors open when not in use and provide adequate venting for fresh air. Also, inspect in, around, and under the sink and around drying rack areas for any outcrops of mold.
3. Moldy, The Movie