Mold Statistics and Facts

Mold is a lot more prevalent and dangerous than most people think. To illustrate just how prevalent and dangerous it is, here are some mold statistics:

Mold Remediation and Prevention Facts

Stats and Facts on Black Mold

  • From our indoor air quality tests, Stachybotrys, commonly referred to as toxic black mold or black mold, was detected in 16% of the samples. (Mold Busters)
  • Mold Statistics by State and City

    In order to know which states are the worst and best places to live for mold allergy sufferers and otherwise mold sensitive people, it’s good to compare various sources and see which places overlap. Below are the worst and best states and cities for mold allergy sufferers and otherwise mold sensitive people ranked based off of the following criteria:

    1. The relative hazard ranking model developed by American Risk Management Resources (ARMR). It is the same model that is also used by the GREENGUARD Environmental Institute (GEI).
    2. A study conducted by Quest Diagnostics that involved the analysis of laboratory test outcomes from patients who visited medical facilities to alleviate symptoms of allergies. The study analyzed approximately 14 million test results from over 2 million patient visits to establish the frequency of allergen sensitivity in the 30 largest metropolitan regions in the United States.

    Worst States for Mold as of 2012 According to ARMR

    1. Texas
    2. Florida
    3. Oklahoma
    4. South Carolina
    5. Nevada
    6. Arizona
    7. California
    8. South Dakota
    9. Tennessee
    10. Kansas

    Worst States for People With Allergies According to Quest Diagnostics

    1. California, was ranked the worst state for allergy sufferers because it has four cities in the top 20 worst cities
    2. Ohio, was ranked second because it has two cities in the top 20. Those two cities were ranked ranked 8th and 10th
    3. Texas, was ranked third because it has two cities in the top 20. Those two cities were ranked ranked 1st and 20th

    Best Cities to Live for Mold Allergy Sufferers and Otherwise Mold Sensitive People According to ARMR

    1. West Virginia
    2. Wisconsin
    3. Massachusetts
    4. Minnesota
    5. Alabama

    Worst Cities for Allergy Sufferers According to Quest Diagnostics

    Note that the percentages next to the cities was calculated based off of the number of allergy patients in that particular city.

    1. Dallas—21%
    2. Riverside-San Bernardino—20%
    3. Phoenix—19%
    4. Los Angeles—17%
    5. Chicago—17%
    6. Minneapolis-St. Paul—16%
    7. Saint Louis—16%
    8. Denver—16%
    9. Kansas City—16%
    10. San Antonio—15%

    What Amount/Percentage of Mold is Considered Harmful or Dangerous?

  • A mold spore concentration that is less than 500 sp/m3 is typically categorized as acceptable. Anything above that mold sore level is considered high and likely problematic. (GreenWorks)

    How Common is Mold in Homes?

    Mold is very common in homes. View these statistics to see exactly how common it really is.

  • 70% of all homes in the USA have some amount of mold in them (Wilson Web Physics, Truth About Mold)
  • A staggering 45 million buildings in the United States have unhealthy levels of mold (Moldy)
  • In the United States, mold problems exist in over 50% of residential properties. (This Old House)
  • A water damage related study was conducted on 100 public and commercial office buildings throughout the United States from 1994 to 1998. The findings revealed that 85% of the buildings had suffered water damage in the past, while 45% were currently experiencing issues with leakage. (U.S. Environmental Protection Agency)
  • Out of all the indoor air quality samples that were tested, only a mere 12% were found to be completely free of mold. (Mold Busters)
  • Mold pros have found 270 different species of mold in properties. (FerroCanada)
  • How Much Does Mold Devalue a Home?

    • Discovering the presence of mold in a property, even after remediation efforts, causes prospective buyers to withdraw their bids in as many as 50% of cases. (The Appraisal Journal)

    Can Mold Kill You?

    Mold is unlikely to kill you on its own, but it does play a major role in causing the death of many people each year. It is well known that mold exposure causes many health issues like weakening your immune system and these health issues can make you a lot more susceptible to dying from other causes like the flu for example. In the medical world, this is called having a preexisting condition. The risk of dying will also go up as you compile other risk factors like how much mold you are exposed to, how long you’re exposed to the mold, how toxic the type of mold you are exposed to is, how old you are, how young you are, and if you have any other preexisting health conditions or not.

    Health and Death Related Mold Statistics

    • 28% of the population carry genes that put them at risk of mold-related health issues. (This Old House)
    • Air pollution, both indoors and outdoors, causes around 7 million deaths per year. (World Health Organization)
    • Over 1 in 4 deaths of kids under 5 years old are attributable to unhealthy environments (World Health Organization)
    • 1.7 million children under the age of 5 die annually due to environmental hazards including but not limited to indoor and outdoor air pollution, secondhand smoke, unsanitary water, poor sanitation, and inadequate hygiene practices. (World Health Organization)
    • Dampness and mold exposure in homes are estimated to contribute to approximately 4.6 million cases of asthma out of the 21.8 million cases reported in the US (EPA and Berkeley National Laboratory, 2007)
    • Infants exposed to extensive mold in their living environments are almost three times more likely to develop asthma than those who are not exposed, according to Michael Pinto (2018).
    • Chronic sinus infections effect effect 37 million Americans and 93% of chronic sinus infections cases can be attributed to mold exposure. (Mayo Clinic)
    • Mold spores may have played a large role in the tripling of the asthma rate in the last 20 years (Mayo Clinic)
    • Identifying mold illness is not part of the standard training for most medical doctors, so most of them don’t know how to diagnose it. “Possibly every doctor in the United States is treating mold illness, and they just don’t realize it.” (Dr. Scott McMahon, MD, 2017)


    Mold is more common and hazardous than than most people think. If you have mold in your property, it’s best that you give us a call right away.