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Can You Sell a House with Mold? Here’s What You Need to Know

At HomeLight, our vision is a world where every real estate transaction is simple, certain, and satisfying. Therefore, we promote strict editorial integrity in each of our posts.

If you think of mold as dark gunk around the tub and shower tiles, it doesn’t seem like a huge problem before selling your house. Just use a strong bleach-based cleaner, and it’s gone, right?

But if it spreads, mold can be a health hazard that affects your home’s structural integrity—and jeopardize your sale. A study by the Environmental Protection Agency found that 21% of the 21.8 million asthma cases in the U.S. can be attributed to exposure to dampness and mold.

“If it’s hazardous and it’s toxic, it tends just to destroy the deal,” confirms Matt Mauro, a top-selling Des Moines, Iowa, real estate agent with 24 years of experience.

So can you sell a house with mold? Here, we’ve answered some common questions so you can sniff out how serious your home’s mold problem is and how to set your place to rights before you put it on the market.

An attic in a house with mold.
Source: (Pxhere)

Know the health and structural risks of mold and the damage it can cause

“Mold” is a general term for the fungi found indoors and outdoors, both in the air and on surfaces, according to health experts at the National Capital Poison Center. Mold is so prevalent—it’s been on Earth for millions of years—that it’s normal for you to have some mold in your home in the form of spores and mold cells. In fact, it’s impossible to remove it all.

Mold becomes an issue once it grows. It thrives in places that are damp, warm, and humid. That’s why most of us notice it in bathrooms. (Mildew is actually a kind of mold.)

Some types of mold, like Stachybotrys chartarum (also known as Stachybotrys atra, or “black mold”), grow on surfaces such as paper, wood, and fiberboard. Others like carpeting, insulation, window frames, and drywall.

Where mold proves most problematic are areas without good ventilation or drainage, such as basements, crawlspaces, and attics. “You get a lot of humidity in your attic, which turns into moisture,” said Mauro. “Because of the humid summers here in Des Moines, the heat is not escaping; the home’s not breathing and ventilating correctly.”

Left to multiply, mold can cause a host of health concerns. It commonly causes allergic reactions, such as hay-fever-like symptoms and rashes, as well as upper respiratory issues such as coughs, sneezing, wheezing, runny nose, and shortness of breath.

The Environmental Protection Agency says that mold can cause asthma attacks in people with asthma and can irritate the lungs, throat, skin, nose, and eyes, even if people aren’t allergic.

Beyond affecting your health, mold also can damage your home’s building materials, furnishings, and belongings.

“Mold needs to eat to survive, and it’s perfectly happy eating your home if you allow it,” notes the Florida Department of Health.

What’s more, if a buyer has an FHA loan, an inspector might find that the overgrowth is dangerous and require you to remove it, according to AdvantaClean, a franchise of light environmental services with more than 225 locations nationwide.

Identify where mold growth is happening

You can see or smell mold. Check for stains or growth that’s fuzzy, velvety, rough, or leathery on furniture, walls, and ceilings. It might be black, brown, white, gray, yellow, or green.

Also look around air conditioning units and furnaces for standing water, and inspect the drain pans, drain lines, evaporator coils, and liner surfaces, health experts say.

Pay attention to any earthy or musty odors. Those usually indicate mold.

A home inspector watches for these signs during a visual inspection. Some home inspectors in Mauro’s area have thermal imaging devices that will pick up damp or cold spots behind the walls, but most of the time, it’s up to your eyes and nose.

Determine the root cause of the mold

If your home seems to be prone to mold, you need to figure out why. Top causes of mold growth include moisture, high-humidity environments, and lack of sunlight, and mold is another reason why water is your home’s no. 1 enemy.

Some mold develops because of your surrounding infrastructure and the age of your home. Newer housing developments might have holdover retention ponds and grading that prevent water from pooling against your home. But older sections might have a house at the bottom of a hill that collects water.

Older construction also can contribute to basement mold through materials, such as concrete block foundation. The type used from the 1950s to the 1980s has supports inside that crack from age, Mauro said. “People are going in and doing drainage tile systems on the inside of them. They’re having to anchor the walls, and they’re having to put iron beams in to brace them. It costs a lot of money.”

Sometimes homeowners inadvertently cause mold through renovations or good intentions.

In Mauro’s area, people wanting to make their homes more energy-efficient have rented insulators to blow insulation into the attic.

Trouble is, they wind up covering the baffles, or chutes that provide air channels through the exterior soffit vents. “The thought is a good thought,” he said. But “if you start blowing insulation over those vents, your attic can’t breathe.”

Source: (Lucas Vasques/ Unsplash)

Your next steps depend on the severity of the mold problem

Whether you buyers will bail if the home inspector identifies mold depends on the amount of growth and location in the home. “If you have an unfinished basement and you have little black dark spots, maybe in the corner of your concrete block foundation, people don’t give that much attention,” Mauro said. In this type of situation, killing the mold with bleach often takes care of the growth.

A finished basement with black mold climbing the wall is a concern, as is mold in an attic or elsewhere that indicates a drainage or ventilation problem.

“It would be up to the buyer, if they wanted to pursue that, to get further tests done by someone who specializes in it,” Mauro said. “They scrape the area, send it into a lab, and get test results back on what kind of mold it is, and therefore how to treat it.”

Informal and formal mold disclosures in real estate: It’s best to be honest

Many states require sellers to disclose any known material defects about their home to buyers with formal paperwork, including a history of mold or fungi and whether it was professionally remediated.

You can ask your agent about your state’s requirements, and HomeLight also has a list of the real estate disclosure forms for every state so you can easily see what the rules are for your area. Check the form for wording such as:

  • Are you aware of any mildew or mold issues affecting this property?
  • Are you aware of any testing for mold on the property?

Other disclosure forms may include “Yes/No: checkboxes with a field for toxic mold and mildew, or feature an advisory to buyers to confirm the status of mold in the house or other biological hazards.

Regardless of what’s required by law, Mauro suggests putting yourself in the buyer’s shoes. “Ask yourself, if you were a buyer, knowing or not knowing, would this affect your decision of buying the home? Could it affect your decision? And if the answer is yes, you need to disclose.”

The issue will also need to be disclosed to future buyers so it’s important not to try and avoid the issue but rather address it head on so you can move forward.

Drywall that is removed in a home with mold.
Source: (Aleksey Boyko/ Shutterstock)

Fix the mold problem professionally and document the work

A mold remediation specialist removes and cleans mold colonies and excessive mold growth, returning the air humidity in your home to what’s considered normal, according to, an online directory of service professionals founded in 2008.

Mold remediation involves using antifungal and antimicrobial cleaners on hard surfaces; sending removable soft surfaces such as sofa cushions and curtains out for cleaning; and replacing porous surfaces such as drywall. The area also is dried with fans and dehumidifiers, then sealed with plastic and negative air pressure.

At least three times in the past few years, Mauro has dealt with sellers who have needed mold remediation before selling their home.

Once sellers produce documentation of the work done, “I’ve been able to make buyers comfortable with that process going forward,” he said. A subsequent mold inspection or warranty helps buyers feel comfortable that “there’s a company that stands behind their work.”

Find out how much mold remediation will cost you

Many mold remediation services offer free inspections. According to, the average cost of mold remediation for basements, crawl spaces, and attics is between $500 to $4,000, with most people paying around $2,000.

However, these costs can grow, depending on where you live and your situation. Mold festering in an attic or along the underside of a roof deck can require tearing off the roof and perhaps sub-roofing, as well as the insulation. It also may involve treating the joists, replacing the baffles, and installing box venting or solar-powered whirlybird fans that improve air flow.

Treating mold that’s gone undetected in an attic can cost as much as $7,000, according to HomeAdvisor.

A homeowner disclosing mold in her house.
Source: (Matthew Henry/ Burst)

Either fix the problem entirely or prepare to disclose and drop your price

There’s a buyer for every house, no matter what the condition is, as long as it’s priced accordingly with its condition. If you don’t have the upfront money and means to fix the mold problem, then you’ll need to compensate for that through the asking price.

But before you reach that point, be clear with your real estate agent about your concerns. Your agent may suggest a home inspection to clarify any structural, mechanical, or safety-related issues, which gives you the opportunity to disclose fully if you can’t make the repairs.

That said, when it comes to mold, it’s wise to fix whatever you can for as long as you’re in the home. As Mauro notes, “Once that’s been discovered, whether you’re staying in the property or selling it, shouldn’t you, for your own health, do something about it?”

Header Image Source: (Burdun Iliya/ Shutterstock)