Causes of Mold


Understanding common causes of mold in the home allows you to take steps to prevent the development of a potentially serious household mold problem. Knowing what causes mold also allows you to prevent a mold problem from recurring if you’ve already dealt with the effort and expense of cleaning up household mold. If you don’t address the cause of the problem, it will likely return and you’ll be faced with cleaning up mold all over again.

Potential Mold Causes

Many different things can cause a household mold problem. Typically things that cause mold growth involve too much moisture in the home, since all types of mold require moisture in order to grow and spread.

Conditions that are often causes of mold in a household include:

  • Flooding (See picture below)
  • A leaky roof
  • Leaky window frames
  • Leaving windows open when it rains
  • Leaky or broken pipes
  • Leaky sinks, tubs or toilets
  • Leaky washing machines or dishwashers
  • Poorly ventilated bathrooms (simply turning on the exhaust fan or opening a window a bit when showering can help with this)
  • Poorly ventilated laundry rooms
  • Damp basements
  • High levels of relative humidity in the home (greater than 50 percent)
  • House fires (mold is actually caused by the water used to put out the fire, not by the fire itself)
  • Any type of significant water damage in the home
Basement Mold From Flood

To prevent mold from developing in the home, correct any of these conditions as soon as possible. That means repairing any leaks promptly. Clean up any water spills promptly, as well. If you have high levels of relative humidity in your home, or if your basement is damp, you can purchase a dehumidifier to reduce the amount of moisture in the air.

The above things aren’t the only possible causes of mold and sometime even the best preventative steps don’t keep household mold from developing. If you notice signs of a mold problem in your home, take steps to address it immediately. Most types of mold grow and spread rapidly, so every day you delay just allows the problem to get worse.

Testing for Mold

If you aren’t sure if you have mold in your home or not, you can have a professional come in and test for mold. This is a good idea after a flood, fire or other event involving significant water damage to the home. If you smell a musty odor in your home, you probably have mold somewhere even if you can’t see it, and you should also have a professional come in and test for mold. By catching mold early, you can prevent a problem from getting much worse. Follow this link to find certified mold testers in your area.

For Help Finding out What Causes Mold in Your Home

If you’ve got a mold problem in your home and aren’t sure what caused it or how to prevent a problem from recurring in the future, we recommend consulting with a mold remediation professional. A trained and experienced professional will visit your home, inspect the areas affected by mold, explain the conditions that led to the development of the mold problem, and let you know what you can do to prevent future problems. Many mold remediation professionals offer free in-home consultations so you have nothing to lose by making an appointment. Even if you want to take care of cleaning up a mold problem yourself, you can benefit from some professional advice about how to prevent future problems. To find professionals offering free in-home consultations in your area, just follow the link.



Return From Causes Of Mold To Our What To Do About Mold Page

Return to Home Page


Mold Prevention

Dangers of Mold

Finding Hidden Mold

Remediation Steps








Causes of mold

A damaged or leaky roof can cause mold.