10 Signs You May Have Mold

Think you might have mold and mildew problems in your home or office?

If you notice the following signs, you should contact a professional indoor environmental specialist to test and confirm mold.


  1. A musty odor. Even if you can’t see visible mold, a musty odor often indicates that mold is growing beneath a surface. If you smell the odor when the HVAC system is on, you might have a problem within the system.
  2. Condensation. Excess condensation on the inside of glass windows, around pipes or on walls could indicate you have humidity control issues and/or a mold problem. Rusted pipes could also mean you have too much water inside your home or office.
  3. High indoor humidity. If you live in a humid area, chances are your indoor humidity is high as well. Your indoor humidity should be between 30 and 50%. Humidity meters and sensors (available from home improvement stores) can let you know if the indoor humidity is too high, requiring a dehumidifier or indoor environmental test.
  4. Discolored walls, wallpaper or ceilings. When indoor moisture is high, you might notice stains or discolorations on walls and ceilings. Usually yellow in color, the stains can become multi-colored if mold is growing. A black light on the area can also indicate mold growth.
  5. Damp interior surfaces. Untreated damp or wet areas, especially floors and carpets, can prompt mold to grow. If your surfaces become wet, dry them as soon as possible. If you notice damp walls or surfaces that have not been exposed to water, you should contact a specialist.
  6. Excess mildew in bath and laundry rooms. Mildew commonly grows in bathrooms, particularly in showers around tile and grout. Normally, you can clean these areas with bleach or soapy hot water. If the mildew seems unusually persistent or black spots form, you should have the space inspected by an indoor environmental specialist.
  7. Water leaks. Leaks around the foundation, roof, plumbing and entrances can easily initiate mold growth. If the leak is not repaired, the continual moisture helps mold thrive. If you notice a water leak or incur water damamge, make sure it’s repaired as soon as possible.
  8. Flooding. If your home has been exposed to flooding, it’s essential to dry all affected areas as quickly as possible, and use a fan to keep air circulating. Even after the area has been dried, mold can resurge, so check the area often for signs of growth.
  9. Warped or cracked surfaces. If your walls are bulging or warped, it could mean moisture is causing the wood behind these walls to swell. Peeling or cracked paint or wallpaper, as well as a musty smell in the area, can also indicate excess moisture.
  10. Persistent allergies and illnesses. Allergies, sinus problems and headaches are common, but if you notice you only have the symptoms at home and/or multiple family members show symptoms, you may want to have the home tested for mold growth.

Think you might have mold and mildew problems?