What percentage of homes have mold problems?

Author: Bernie Gibson  |  Last update: Tuesday, October 7, 2025

In a 2022 report, the National Institute for Occupational Safety and Health Centers for Disease Control and Prevention estimated that around 47% of all homes in the United States have some mold or dampness, based on several published studies.

How common are mold problems in homes?

Approximately 70% of homes have some kind of mold in them. People with asthma, allergies, or other breathing conditions may be more sensitive to mold. At least 45 million buildings in the United States have unhealthy levels of mold. Keeping humidity levels under 50% will prevent mold growth.

How much mold is in the average house?

A normal mold spore count in a room is typically 200-500 spores. Anywhere between 1-1500 mold spores in a room is normal and safe as long as mold colonies are not visibly growing and no water damage is present. Mold spores are present in virtually every room of every building.

Is it normal for houses to get mold?

It's not at all uncommon to find mold in your home, especially if you live in a humid climate. Mold can grow anywhere there's moisture, so it's important to be vigilant about checking for it and cleaning it up as soon as you spot it.

Can you still live in a house with mold?

As long as you are not an allergic person, you should be able to live with mold in your house but it is always a good idea to keep your house clean and free of mold. Mold can cause a lot of health problems, especially if you are someone who is allergic to it, but there are ways to get rid of it if you need to.

1. When Mold in the Home Is a Problem (English)

Is it worth buying a house with mold?

However, there are some significant dangers to buying a house with mold growth. If left untreated, mold will soon spread to other areas of a home and may cause health troubles and expensive home repairs. If you're thinking about buying a property with some kind of mold problem, you may want to think again.

What are signs of mold sickness?

Although symptoms can vary, the most common symptoms seen in people exposed to mold indoors include:
  • Nasal and sinus congestion.
  • Eye irritation, such as itchy, red, watery eyes.
  • Wheezing and difficulty breathing.
  • Cough.
  • Throat irritation.
  • Skin irritation, such as a rash.
  • Headache.

Do all old houses have mold?

If constructed right, you can find a 50-year-old house with negligible mold problems.

How to get rid of mold on walls permanently?

The only effective way to permanently get rid of mould problems is by reducing the build-up of moisture in your home. This can only be achieved through better ventilation.

Does opening windows help with mold?

Mould thrives in damp areas such as windows, where there is dust, dirt or organic material, that's why the number one way to reduce mould is to open your windows regularly. By opening the windows at least once a day, this allows the mould spores to escape and lets patches of moisture dry out.

What states have the most mold problems?

Worst States For Mold

Texas ranks #1, and following Florida is Oklahoma, South Carolina, Nevada, Arizona, California, South Dakota, Tennessee and Kansas. It sounds bizarre that dry states such as Nevada and Arizona could rank so high for mold occurrence but it is possible.

Can a home be 100% mold free?

Your home can be free of significant mold growth such as visible mold colonies growing on different surfaces, but it would be nearly impossible to be completely free from mold spores.

How to tell if your house is toxic?

If you suspect your asthma worsens or is more severe than usual, contact your doctor or medical professional.
  1. Bad Smells In The Home. When there's a bad smell in the home, you can tell. ...
  2. Peeling Wallpaper. ...
  3. Spots On The Wall. ...
  4. Bad Allergies Won't Go Away. ...
  5. Visible Mold Growth. ...
  6. Past Water Damage.

Where is mold most likely to grow in house?

To prevent mold, toxic mold, and mildew, make sure you are inspecting these 14 places where mold can thrive in your home.
  • Basement. Your basement is likely the most common place where you will see mold. ...
  • Bathrooms. ...
  • Kitchen. ...
  • Attics. ...
  • Crawl Space. ...
  • Laundry Rooms. ...
  • Underneath Flooring. ...
  • Air Conditioners.

How to stop worrying about mold?

Clean your home and clothes with non-toxic mold-specific products. Inspect for leaks and water damage regularly, addressing problems immediately. Remove shoes and coats at the door to reduce contamination from the outside environment. Use sensors, fans, and dehumidifiers to monitor and control indoor moisture levels.

What is the number one cause of mold?

1. Insufficient Ventilation. In areas like bathrooms and older homes lacking proper ventilation and exhaust fans, excess moisture from hot showers can get trapped. This trapped humidity settles on various surfaces, creating a conducive environment for mold growth.

What kills 100% of mold?

Hydrogen peroxide, commonly used to disinfect wounds, is active against a wide variety of micro-organisms including mold. It acts by releasing oxygen at a rapid rate, which kills mold by oxidizing the surface and breaking down proteins and DNA.

Can you paint over mold?

While painting over mould may temporarily disguise the problem, paint alone will not kill mould. Instead, the mould will continue to grow underneath the paint until it begins to show through. It may also cause the paint to bubble or flake, ruining the finish. If possible, it's best to remove the mould before painting.

Does mold in a house ever go away?

The most important thing you can do is get rid of mold and dampness as quickly and safely as possible. Mold problems will not go away unless moisture problems are fixed. It is not important to have someone measure how much mold there is or to find out what kind of mold it is.

What percentage of homes have mold in them?

A 2022 report from the National Institute for Occupational Safety and Health Centers for Disease Control and Prevention estimated that around 47% of all homes in the United States have some mold or dampness. Seeing mold is a clear sign, but sometimes you can smell mold.

Does mold remediation actually work?

Mold can be successfully remediated. Mold remediation can treat the area and prevent it from spreading to other spaces in the home. Remnants of dead mold may remain, and this should be encapsulated with paint.

How long does it take for mold to make you sick?

According to the CDC, people usually experience their first symptoms within 2 to 9 hours of their first exposure. On the other hand, some people could go for weeks or months before feeling sick if their exposure is limited enough. This is why it is also important to check damp, dark areas of your home for mold.

How to find hidden mold in your house?

Most often, a mold problem will be readily identified by a musty smell that becomes obvious in damp environments. Mold also likes to play hide and seek, so if you suspect there is a problem, then check under carpets, behind drywall, inside ductwork, in between bathroom tiles and in other moisture-prone areas.

What does black mold smell like?

Toxic black mold growth has a more potent and identifiable smell, like the smell of decay, wet soil, or rot. Visually, it may be greenish-black, grayish-black, slimy, or more furry than other forms of mold or mildew.

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