The Top 5 Moldiest States To Live In

By: Licensed Mold Assessor Brad Fishbein

February 8, 2023

If you live in America, no matter which state you live in, there will be some mold found in your home.

This holds true for anywhere else in the world. Fungi in living spaces, is naturally occurring, and there is simply no way to eliminate it completely.

However, some states are more susceptible to mold compared to others. This article will explore the top five moldiest states to live in

Here are the qualities that fit the criteria:


The USA has many different climates. Whether you are in the pacific northwest, the Northeast, Middle America, The Southeast, or any other areas, each climate has different qualities and some are susceptible to a natural disaster, which makes it unique.

The two qualities we will take into account when establishing the moldiest states are precipitation and humidity.


The list of states with the highest precipitation was not what you would expect.

You would tend to think a state in the Pacific Northwest such as Washington would be up towards the top of the list, right?

Well, it’s actually in the bottom half.


In 2019, the state with the highest precipitation in inches was Mississippi.


It’s a fact that without high relative humidity, mold will have a tough time growing. Any mold inspector that comes into your home looking for mold will measure the moisture in the air before anything else.

Humidity is essential when finding a mold issue in a home.

Regardless if you have a leak or not, if you have high humidity, you may have such issues as white mold on your clothing, furniture, or any other personal belongings.

Mold will attach itself to porous surfaces under humid conditions and start to colonize.

One common misconception is that just because it is hot outside means that it cannot be humid. That is not true.

Humidity and temperature are two completely different things.

If you were one of the people that thought the weather has to be hot for it to be humid, you would be shocked that Alaska is ranked as the most humid state.

Water Damage Claims

The next piece of data that was looked at when determining the moldiest states was the insurance industry.

The amount of water damage insurance claims and the cost of premiums were investigated.

Looking at the cost of homeowners insurance per year would be deceiving because some states near the top of the list were on there because of other natural disasters such as Oklahoma (tornados).

Water damage and mold insurance claims have hit an uptick in recent years.

There are multiple reasons why, including:

  • Homes are getting older, so plumbing issues start occurring
  • Fraud
  • The rise of public adjusters

Regions that have higher precipitation, which can lead to more roof leaks is also a factor.

States with higher relative humidity and high temperatures will have the HVAC system running more frequently, which can cause air conditioning leaks. That is another peril that must be accounted for.

Building Design and Lifestyle

The type of construction and year homes are built played a significant role in determining which states have the most mold in homes.

Houses are designed differently in certain parts of the country, and people have different habits depending on their geographical location as well.

For example, areas of the country with a high percentage of homes built in the ’80s and ’90s may have more plumbing issues due to polybutylene plumbing.

Other areas of the country may open their windows more than running the air conditioning.

So, Let’s take a look at the top five states where mold problems can arise.

Number 1- Florida

Florida takes the cake here. It’s the home of many things such as Mickey Mouse, hurricanes, palm trees, The Everglades, and overall craziness!

Florida is also home to the state where you are most likely to have a mold issue.

Water damage claims jumped 46% from the period of 2010-2015.

There are have been so many claims for water damage over the past decade that the state decided to change their insurance laws in 2019 to help.

Some of it is the rise of insurance fraud, but no doubt, there is plenty of mold in the state of Florida.

Air conditioning units need to not only cool, but they must dehumidify adequately in the state of Florida.

Being in the Southeast, the weather is warm and humid all year long, which is a prime opportunity for mold to grow. Also because homes in Florida have air conditionings that are running very often, there is more opportunity for mold to go through the HVAC ductwork.

Not to mention, the 20 minutes rainstorms with the wind in the spring and summer months can cause water intrusion into homes.

Number 2- Louisana

Everyone is aware of the havoc that Hurricane Katrina caused in the state of Louisiana, especially in New Orleans.

But Louisiana is one of the most humid states there is.

During summer months, it can be even muggier than Florida.

Add that on top of the fact it’s a lot of swampland and it can be a recipe for fungal growth.

Real estate in Louisiana is also mostly newer.

According to a study done in 2018 by the American Community Survey, only about 11% of the homes were built before 1950. Around the 1950s is when construction materials were starting to become more cellulose-based, which supports mold growth.

According to the National Association of Insurance Commissioners, Louisiana also had the highest average insurance premiums in the country in the year 2017.

Needless to say, Mardi Gras and Gumbo can get quite moldy!

Number 3- Texas

They say, “Everything is bigger in Texas,” They may also be referring to mold problems because Texas has its share!

Texas is one of the first states to put mold licensing laws into place in 2004. Being at the forefront was necessary.

Along the coast during the early part of the 21st century, the state saw a sharp uptick of mold damage claims. It hasn’t stopped either. Texas is up there as a state with one of the most amounts of water damage claims.

While humidity isn’t the first thing you think of when you think of the Lone Star State, it really depends on what Texas region you are in.

Springtime can be quite humid.

Texas is one of the fastest-growing states over the past 40-50 years. Newer construction means more porous materials, just like Louisiana.

Number 4- Mississippi

Mississippi is certainly not thought about when you think Hurricane Katrina. You generally think of New Orleans. However, Mississippi had $30 Billion worth of damage. The gulf coast took quite the hit.'

Not only is Mississippi the number one of the most humid states and have the most precipitation, but it also has some of the highest homeowner's insurance premiums.

Also making the argument is that the numbers may actually be higher than reported is looking into the economic status of families in Mississippi.

Mississippi has a growing real estate market as well as the economy before the pandemic. Still, at approximately $43,567 median home income in 2018 according to the US Census Bureau , it ranks near the bottom of the states in that category.

Why does that matter?

Well, Quest Diagnostic Studies put together a study that found that economically disadvantaged children are 18% less likely to be tested for allergies than economically advantaged children. This means fewer people, specifically children, are being tested even to realize mold is an issue.

When money is an issue, mold falls to the bottom of the totem pole.

This slot could have also easily been Alabama due to coastal flooding.

Number 5- California

Considering California is an arid part of the country, mold is often overlooked. However, it shouldn’t be.

While California is not known for humidity or rain, The Golden State as a whole still has more than double the amount of precipitation compared to another Western state like Nevada.

The summer months are also more humid than you would think. For example, if you look at June 28, 2020, here are the comparisons for the humidity of Los Angeles vs. Miami.

As you can see, it’s actually more humid in Los Angeles.


This is just one particular day that is being compared; the point is there is humidity in California.

To further elaborate on the issue of humidity in California, many homes are not built with central air conditioning.

While these houses that don’t have central air conditioning have a ventilation system that works fine, the trouble arises when a leak occurs during these humid times.

If not dried up properly, mold can start to grow under the right conditions. Mold spores can then become airborne, and fragments of mold spores may be found within porous materials in your home, such as your clothes or within your carpets.

A factor of mold being present in California homes is because it’s often overlooked.

With PM 2.5 and other air quality issues, you can see why.



While these are the top five moldiest states to live in, you can have a fungal issue in your home in any state.

The key issue is controlling moisture.

If you control moisture either due to a leak or humidity, you should be perfectly fine!

Meet the author: Brad Fishbein is an ACAC council-certified Microbial Investigator. In the fall of 2012, he became a Licensed Mold Assessor in the State of Florida through the Department of Business & Professional Regulation. Brad has helped homeowners with over 5,000 successfully completed Mold Inspections since 2009.

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