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The 3 Worst States to Live In if You’re Sensitive to Mold

by Amanda Demsky
mold allergy free states

It’s a well-known fact that high humidity can facilitate significant mold growth, but it may come as a surprise to many that the regions with the highest levels of humidity are not the only places that present the biggest mold problems. While long damp seasons are a major factor in mold growth, there are other risk factors that those with mold sensitivities or mold allergies need to take into consideration before a move.


Besides Humidity, What Other Factors Play a Role in Regional Mold Growth?

A significantly overlooked factor of regional mold growth is building construction and building maintenance practices. You may think that building materials and building practices are the same throughout all the States, but this is simply not true. Some regions depend on masonry, others mainly wood-based materials, others stone, and still others rely more heavily on materials such as concrete. The porosity of each material varies, as does its natural or man-made resistance to mold. Some regions have building codes that require more moisture-resistant materials, while others do not have such building codes despite their high humidity climate or the location’s propensity toward natural water disasters.

While indoor mold growth is evenly distributed throughout all 50 States—and is not commonly the result of exterior humidity—only specific molds proliferate in particular building materials or in regions that use the same materials but have specific building codes and practices. For instance, a 2011 study on mold determined that the type of mold along the east coast differs from the west coast. As an example, Aspergillus was found mainly in homes across the eastern United States, while Penicillium was found primarily in the West.

As mentioned before, what’s interesting is that all types of mold are prevalent in every State, so the only determining factor between what type of mold takes hold the most in these regions is dependent entirely on the building materials and maintenance practices.

The 3 Worst States to Live In if You Have Mold Sensitivities

This begs the question, which States tend to use building materials and practice building maintenance in a way that permits and inadvertently supports structural mold growth? This is the very question that researchers are trying to answer as they are starting to see undeniable evidence that unique building practices make a difference.

Thus far, they have been able to determine that there are over 30 cities (many within the same few states) that have presented the most cases for hospitalization and out-patient services for patients suffering mild to severe cases of mold allergies.

The top ten worst cities for mold allergies (based on medical reports) are as follows:

1: Dallas, TX—21% of all allergy patients
2. Riverside / San Bernardino, CA—20% of all allergy patients
3. Phoenix, AZ—19% of all allergy patients
4. Los Angeles, CA—17% of all allergy patients
5. Chicago, IL—17% of all allergy patients
6. Minneapolis / St. Paul, MN—16% of all allergy patients
7. Saint Louis, MO—16% of all allergy patients
8. Denver, CO—16% of all allergy patients
9. Kansas City, MO—16% of all allergy patients
10. San Antonia, TX—15% of all allergy patients

While we cannot supply a comprehensive list of every moldy city in the United States, we can provide you with the researchers’ assessment of the top three worst states using the same medical statistics. By assessing which states presented the most cases of mold allergy patients, researchers have determined that California, Ohio, and Texas harbor the moldiest cities and structures in all of the United States.

1st: California, with four cities in the top 20 worst cities for mold allergy sufferers.
2nd: Ohio, with two cities in the top 20, ranked eighth and tenth for mold allergy sufferers.
3rd: Texas, with two cities in the top 20, ranked first and twentieth for mold allergy sufferers.

In addition, the southwestern United States is decidedly worst region overall for mold allergy sufferers. It harbors four of the top five worst cities for mold sensitization.

That said, keep in mind that this is entirely dependent not only upon mold victims reporting and seeking medical assistance, but also medical professionals diagnosing them as mold allergy sufferers or toxic mold victims.

One of the most important pieces of information we have shared repeatedly on MoldBlogger is the fact that mold sufferers often don’t recognize their symptoms as doctor visit-worthy, nor do their doctors recognize and accurately diagnose their symptoms as mold toxicity. Instead, victims often try to manage symptoms at home or their doctors misdiagnose them completely.

Regardless, there are enough statistics already to determine that California, Ohio, and Texas are becoming well-acquainted with mold allergies and mold sickness at an alarming rate, which does lead one to believe they truly are the top three worst states concerning mold exposure.

Before Your Move: How You Can Make an Informed Decision Regarding Regional Mold

The National Allergy Bureau monitors each region and provides a mold spore tracker that permits you to not only check the counts and types in your current area, but wherever you might be considering a move.



Exposure to mold can seriously affect your health. Research has revealed that the presence of mold in the structure of a home—not just an isolated growth indoors—can induce childhood asthma, as well as trigger the worsening of autoimmune diseases. Therefore, it is imperative that you not only practice excellent home hygiene and maintenance, but that you ensure you haven’t moved into a home or region that is rife with mold growth, especially if you suffer from asthma, allergies, or have any underlying health conditions, such as imbalanced hormones or autoimmune disorders.

Other Building-Related Mold Topics on MoldBlogger:

How to Build a Mold-Resistant Home or Commercial Building
How to Prevent Mold During Construction
The Effects of Mold on Building Material
Designing Your Kitchen to Be Mold Proof

For more information regarding mold, mold prevention, and mold solutions, please check out the rest of MoldBlogger.com.

Article by Amanda Demsky from the MoldBlogger team.

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