The dreaded mold. Many of you will have experienced this in your home firsthand. But just how widespread is it? And how much of a problem is it causing? We take a look at this in our mold statistics round-up for 2024.

Quickfire Facts and Figures

If you just want the quick facts and figures, this section is for you. Here are the most important mold statistics from our research:

• Two-thirds of people in the USA have experienced mold of some form in their home (either current or a past home) 
• Almost a quarter say they have experienced a serious mold issue
• A visible mold issue could shave over $99,000 off the resale price of an average house in the United States
• An estimated 47% of buildings in the USA have a mold problem
• Mold is thought to be the cause of over a fifth of asthma cases in the USA

How Many People in the USA Have Experienced Mold in Their Homes?

In April 2024 we polled 2,000 people aged 18 and over across the USA to find out how many of them had experienced mold in their homes. Here’s what we asked:

• Have you ever experienced a mold problem in a home you were/are living in?
  • No, never
  • Yes, I have experienced a minor mold issue in my home
  • Yes, I have experienced a moderate mold issue in my home
  • Yes, I have experienced a serious mold problem in my home
  • Prefer not to answer

Here is how they responded:

Response	Proportion of Respondents
No, never	21%
Yes, a minor mold issue	19%
Yes, a moderate mold issue	32.4%
Yes, a serious mold issue	14.6%
Prefer not to answer	13%

In other words:

• Two-thirds of people in the country say they have experienced a mold issue in their home
• For 14.6%, they considered this to be a serious mold issue
• Just under a third have experienced what they consider a moderate mold issue in their home
• While almost 1 in 5 have had a minor mold issue in their home

Of course, people’s perceptions of the severity of their mold issues can be subjective. In addition, the question allowed people to answer yes even if this was a previous home and not their current home.

So we’re not saying that three-quarters of homes in the United States have ongoing mold issues.

Nonetheless, it’s evidence that mold in homes is incredibly common.

Throughout this article, we reference data from a number of organizations that have attempted to estimate the prevalence of mold in homes.

The Prevalence of Toxic Mold in the USA

A NIOSH report published in 2022 assessed a number of previous studies in an attempt to estimate how many homes across the country have mold. It estimated that figure at 47%.

There remains little research into the prevalence of mold in public buildings like schools, however. But estimates suggest that some 45 million buildings in the USA have unhealthy levels of mold.

Although there’s no recent data about the prevalence of mold specifically in school buildings, we do know that issues known to cause mold are prevalent in schools.

30% of schools in the USA have plumbing problems while 27% have roofing problems that could lead to indoor or outdoor water leakage

Mold and Health

A 2016 study estimated that allergic rhinitis caused by exposure to indoor dampness and mold costs Americans $3.7 billion every single year.

In addition, acute bronchitis relating to mold exposure costs around $1.9 billion per year.

Data from the World Health Organization estimates that 21% of asthma cases in the USA could be linked to dampness and mold too and that removing damp from the home reduces symptoms by 25% to 45%.

Another report suggested that as many as 93% of chronic rhinosinusitis cases can be attributed to mold exposure. This report also found that in 94% of cases, patients suffering chronic rhinosinusitis were able to significantly improve their condition – to the point of having normal endoscopic exam results – by reducing their exposure to mold.

Mold and the Value of Your Home

Toxic mold doesn’t only have a negative effect on your health. It can reduce the valuation of your home as well, ultimately meaning you pocket less for your house if you sell it with visible mold.

An Appraisal Journal report suggested your home resale price could be cut by 20% to 37% if there’s visible mold inside. With the average USA house price at $495,100, it means the average house could see $99,000+ shaved off of its valuation.

So there are financial incentives to preventing mold too.

Searching for Solutions

One way to gain insight into how prevalent an issue is, is to take a look at online searches pertaining to that issue.

As with most things, people experiencing a mold issue in their home will often go to search engines like Google to find out more about it, including what they ought to do in order to fix the issue.

With this in mind, we took a look at the number of searches per month across the country in Google USA for things relating to mold, and here is what we found.

Keyword	2020	2021	2022	2023
how to get rid of black mold	162500	166900	181500	219600
how to remove black mold	162500	166900	181500	219600
how to remove mold from walls	63800	89400	104400	135100
how to clean mold off walls	32800	42400	49800	58000
how to get rid of mold on walls	63800	89400	104400	135100
how to clean black mold	39700	42900	49800	58800
how to remove mold from shower	67200	77100	75600	91500
how to get rid black mold in shower	23100	28800	27800	31800
Total of all the above queries	615400	703800	774800	949500

• In 2020, there were 615,400 searches in Google USA for the selection of keywords we analyzed. By 2022 this had risen to 949,500 – an increase of 54% in just 3 years.
• Of the 8 searches we analyzed, all are being searched more now than they were in 2020. The most significant proportional growth, however, is in searches for “how to remove mold from walls,” where an increase of 111.8% between 2020 and 2023 saw last year’s total searches at 135,100.
• The close variant, “how to get rid of mold on walls,” exhibited the same increase.

Mold and Social Media – The Statistics

Long gone are the days when Instagram was for photos of your fancy food and TikTok for sharing videos of your cat.

It seems hundreds of thousands of us are now using social media platforms as a means of sharing our hacks for getting rid of mold and even sharing our mold problems with millions of people.

• There are over 1,000,000 posts on Instagram with the hashtag #mold at the time of writing (April 2024)
• There are 37,600+ posts with the hashtag #blackmold
• There are over 138,000 posts on Instagram with the hashtag #moldremoval

We’re TikToking our mold issues too. 

• This video about hidden mold in the home has racked up over 16 million views at the time of writing.
• A TikTok search for “mold removal” returns hundreds of videos with the most viewed having over 4 million views to date. Several others have amassed 2+ million as well.

Meanwhile on Youtube:

• The Home Depot’s video on getting rid of mold has 1.1 million views to date
• Another has over 800,000 views

A Doctor’s View on Mold

We spoke to UK Doctor, Nazreen Morley, about the impact of mold on your health. She told us:

“We know that living in moldy conditions can have a range of negative effects on your health. I frequently see patients exhibiting symptoms that, in some cases, are attributed directly to mold. 

Those with respiratory conditions such as asthma can find their symptoms triggered or worsened by exposure to mold. And similarly, they can also worsen conditions like bronchitis and pneumonia. They can cause allergies, eye problems and skin problems. In rare, but extreme, cases, mold poisoning can also occur, which presents with symptoms like fever, chills, muscle pain, and breathing problems. 

Chronic Inflammatory Response Syndrome (CIRS) is another condition caused by exposure to mold, which presents with symptoms like fatigue, weakness, muscle aches and cramps, headaches, and even red eyes. It can also cause light sensitivity and headaches.

Studies also suggest that black mold can be at play in worsening the symptoms of long COVID. 

For those who suffer from Chronic Fatigue Syndrome (CFS), which is also referred to as ME, black mold is a known trigger. 

There’s also an increasingly clear connection between mold and Multiple Chemical Sensitivity (MCS). And we have to be clear that MCS is often much more life-affecting than simple allergies (which respond to antihistamines typically). MCS is clearly linked by NIH to toxic mold exposure.

So if you do have a mold issue in your home, it is certainly in the interests of your health to look to remedy it.”

So What Can You Do About Mold?

Prevention is better than cure, as they say. So we’d recommend taking a look at our mold prevention guides and checking out other resources we have listed here.