How to Prevent Black Mold Exposure in Your Home

Woman lifting corner of wallpaper to reveal black mold

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Without mold spores, we would not have penicillin, Roquefort cheese, and leaf mold-enhanced soil that benefits gardeners and farmers. However, there are some dangerous molds—like black mold—that invade our homes and workspaces and can cause a number of health issues.

Once black mold has taken hold in a home, it must be eradicated. And, using extreme caution and protective gear, you can remove small areas yourself. However, because it grows so quickly, black mold usually requires a licensed professional to safely remove it from a home.

If the black mold infestation covers 10 or more square feet, a professional should handle the removal. Removing large mold colonies requires exposure to heavy-duty chemicals and permits for the proper disposal of infected building materials. Local public health departments can offer advice on mold testing and refer you to an expert mold remover.

What Is Black Mold?

Stachybotrys chartarum, more commonly known as black mold, appears as a colony with a dark green or black slimy surface. It is most often found in areas inside a home that have been exposed to excessive amounts of water and humidity for an extended period of time.

While not always readily visible, black mold can develop behind sheetrock walls and ceilings on wood infrastructure. S. chartarum produces mycotoxins, or potentially poisonous chemicals. Exposure from skin contact, inhalation, or ingestion may be dangerous to humans and animals.

Because so many molds look similar and emit a musty odor, the only way to be certain that your home is infested with black mold is through professional testing. However, almost all types of mold that are growing in large colonies in a home have the potential to be harmful to your respiratory system and should be removed, with measures taken to prevent regrowth.

Stachybotrys mold

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How to Manage Black Mold Exposure

If you have discovered black mold in your home, there are steps you can take to help limit your exposure until the colony is cleaned away.

  1. Stop the Moisture Source

    If the mold is growing near a persistently leaky sink, tub, or toilet, turn off the water or repair the leak. Cover roof or window leaks with a plastic tarp until they can be repaired.

  2. Seal off the Infested Area

    If possible, seal off the portion of the house that has black mold by taping plastic sheeting over the doors. If the leak has been repaired and the area is dry, lightly spray the mold with water to prevent the spores from becoming airborne.

  3. Wear a Mask

    When entering areas with black mold, wear a mask that is rated to prevent the inhalation of mold spores and disposable protective gear or clothes that can be washed in hot water.

  4. Clean Safely

    If you are cleaning the mold-infested area yourself, use the chemicals properly and clean surrounding to prevent spread.

  5. Dispose of Cleaning Materials Properly

    Place cleaning supplies, disposable protective gear, and plastic sheeting in a sealed heavy-duty plastic bag so that the spores will not travel to other areas.

How to Prevent Black Mold Growth

Since mold spores are everywhere, even in dry climates, it is possible for a colony of black mold or other toxic molds to form in your home. However, there are steps you can take to help prevent the growth of any type of unwanted mold.

  1. Control Humidity Levels

    Mold needs moisture for growth. To prevent this, ensure the humidity level in your home never rises above 60 percent.

  2. Repair Leaks

    Just a small leak can cause wood, drywall, grout, and other porous surfaces to become a welcome spot for mold growth. Promptly fix leaky pipes, fixtures, windows, and roofs.

  3. Keep Fabrics and Surfaces Dry

    Never leave wet coats, shoes, or towels in a heap. It takes only two days for mold to take hold, begin to grow, and smell musty. Hang your wet items so they dry more quickly.

    Be sure to dry shower stalls and tubs with a squeegee after every use. Save wet jobs like mopping floors, steam cleaning fabrics, or power-washing surfaces for a warm, breezy day so the surfaces dry quickly.

  4. Improve Ventilation in Your Home

    Make sure you are using bathroom and kitchen fans when cooking to remove steam and speed drying. The addition of ceiling fans and circulating fans are a great help when the humidity is high. Open doors and windows on dry, breezy days.


    Be sure to also open small spaces like closets often so that moisture can escape, and make sure your HVAC vents are not blocked by furniture.

  5. Use a Dehumidifier

    If the humidity is high in your basements or laundry room, use a dehumidifier to remove moisture from the air. Be sure to maintain the appliances well and empty the water collection bin at least daily.

  6. Check Ductwork and Venting Systems

    You should always check and clean your HVAC ductwork and clothes dryer ductwork at least once a year to prevent clogs or leaks that allow moisture back into your home.

  7. Install Moisture Barriers

    Basement areas and crawl spaces are prone to excessive moisture. Install moisture barriers where needed and use specialty coatings to make sure moisture from the earth is not entering the space.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Basic Facts About Mold and Dampness. Centers for Disease Control and Prevention.

  2. Mold Cleanup in Your Home. United States Environmental Protection Agency.

  3. Facts About Stachybotrys Chartarum. Centers for Disease Control and Prevention.

  4. A Brief Guide to Mold, Moisture and Your Home. United States Environmental Protection Agency.