Mold: Is It Hiding in the Home You're Buying?

Recognize potential mold problems before buying a house—and get the seller's full disclosure for mold problems you can't see.

By , J.D., University of Washington School of Law

No one wants to buy a house with a mold problem. Unfortunately, these sneaky little spores aren't always easy to detect. If you're house hunting, you'll want to learn how to:

  • evaluate the risks
  • detect mold in homes
  • get the seller to disclose mold issues, and
  • negotiate around any mold problems that come to light in the course of the sale.

That's what this article will discuss.

(To learn about mold in rental units, read Mold in Rentals: Landlord Liability, Responsibility, and Prevention.)

The Trouble With Mold in the Home

Mold is a fungus that comes in various colors (black, white, green, or gray) and shapes. While some molds are visible and even odorous, mold can also grow between walls, under floors and ceilings, or in less accessible spots, such as basements and attics. Mold does best in water-soaked materials (paneling, wallboard, carpet, paint, ceiling tiles, and the like), but can survive in almost any damp location. Mold can grow in houses situated in the desert, and it can grow in homes in hot and humid climes.

Here are common places in a home where mold is likely to take hold:

  • around leaking pipes, windows, or roofs (the constant supply of water gives mold spores the start they need)
  • basements or other places that have flooded and not been thoroughly dried
  • tightly sealed buildings (common with new construction), which trap excess moisture inside, and
  • homes with poor ventilation, numerous over-watered houseplants, and housekeeping habits that ignore obvious dampness and don't include airing the place out.

Besides presenting an ugly appearance and sometimes an unpleasant odor, mold can cause health problems. A few types of molds produce mycotoxins, which can cause rashes, seizures, unusual bleeding, respiratory problems, and severe fatigue in some people. Fortunately, most molds are of the non-toxic variety.

For more on the hazards of mold, see Toxic Mold Health Risks and the resources listed below.

How to Detect Mold in a Basement or Home

You won't always know if there is mold in a house you're considering buying, but you can take a few easy steps to try and find out.

Be on the lookout for mold. When thinking about buying a home, look for the elements above to figure out if there are any obvious signs of mold or the potential for it to grow. Keep your eyes peeled for standing water in the basement, water marks on walls (particularly recent-looking stains), or musty smells (particularly in bathrooms, kitchens, laundry rooms, basements, cabinets with plumbing, or other areas with plumbing).

If you're looking at a newer home, find out whether it is built with "synthetic stucco," also called the Exterior Insulation and Finish System (EIFS). This airtight barrier is supposed to improve insulation but, if improperly installed, may allow water penetration and mold growth on the inside of walls.

Ask your home inspector. If you have the home professionally inspected before buying, your home inspector might see obvious signs of mold or water damage. While it's not the inspector's job to look for mold, most home inspectors will mention obvious signs of water damage and the possible presence of mold. And, because inspectors poke around in spaces you might not, they might see things you wouldn't. For more information, see Getting a Home Inspection Before a Real Estate Purchase.

Don't hesitate to ask whether the inspector saw signs of mold or potential mold dangers, and ask that these results be included in the inspection report. Some inspectors might be wary of this, wanting to avoid liability for mold-related problems. But all should be comfortable talking to you about whether they saw anything suspicious or that warrants bringing in a separate professional.

Ask the seller to disclose any mold or water-related problems. Some states, including California, require sellers to disclose information about mold. Keep in mind that the seller's duty to disclose only relates to things the seller knows about or reasonably should know about: Sellers don't have a duty to go poking around in the walls to see if there's mold, for example.

In states where mold disclosure is not required, you can still ask for such disclosure. In addition, you could ask questions about things that might lead to mold growth, such as "Have any pipes ever burst?" or "Have any of the windows ever leaked?"

For details on state disclosure requirements, see Required Disclosures When Selling U.S. Real Estate.

Listen to agents and appraisers. In some states, real estate agents or brokers have a duty to disclose problems they know about. Likewise, an appraiser should notify you of any obvious sign of a mold problem if it could affect the value of the property.

Add a mold-related contingency to your offer. Assuming you're interested enough in the house to place an offer on it, making the sale contingent on your satisfaction with the results of specific inspections for mold lets you back out if the inspection finds a mold problem. Unfortunately, tests for mold are difficult to conduct and expensive. And, according to the U.S. Environmental Protection Agency (EPA), testing for mold isn't usually necessary when it's visible on surfaces. Most people will end up relying on the detection methods discussed above.

Nevertheless, if you have reason to suspect there's hidden mold in the home, you might elect to hire a professional mold testing company. These companies test the air in and around the home. They can also dig into walls and take samples, which they later test in a laboratory. Testing the air usually costs several hundred dollars. If the company takes wall samples, the cost will be even higher.

Should You Buy a House With Mold Problems?

If you find a house and discover it has mold problems, should you buy it anyway? If you or a family member has asthma or if a baby or an elderly person will live in the house, you'll want to be especially concerned. You'll have to decide whether the cost of removing the mold and fixing the source (both in terms of time and money) is worth the price you'll pay.

If you have an inspection contingency in your purchase contract, and the mold is revealed as part of the inspection, or if you have a specific mold contingency, you have a bargaining chip. You can ask the seller to reduce the asking price or to fix the problem. Alternatively, you can choose to walk away from the deal. (To learn more about inspection contingencies, read Contingencies to Include in Your House Purchase Contract.)

What If The Home Seller or Builder Did Not Disclose a Known Mold Problem?

If the prior owner of a house you bought knew of the presence of mold and was required to disclose this information under state real estate disclosure rules, but did not do so, the owner could be liable to you for failure to disclose. See Who to Sue for Toxic Mold for more on the subject. Other useful articles include Home Defects: Sue the Seller, Agent, or Property Inspector, which provides useful advice on determining who's legally responsible for home defects and how to file suit. For advice on dealing with problems in a new house, see New-Home Defects: Holding Your Builder Responsible Under a Warranty.

Resources and State Laws on Mold in Homes

The U.S. Environmental Protection Agency (EPA) provides extensive information on mold, including advice on cleaning up mold after a flood in your basement. The Centers for Disease Control and Prevention (CDC) also offers useful resources on mold on its website.

Most of the mold-related regulations occur at the state level. For example, California, Indiana, Maryland, New Jersey, and Texas have passed legislation aimed at developing guidelines and regulations for mold in indoor air. Try checking the state agency responsible for mold and indoor air quality, or monitor the National Conference of State Legislatures (NCSL)'s Environmental Health Legislation Database, which tracks state legislation on environmental health hazards, including mold.

For more practical homebuying tips, get Nolo's Essential Guide to Buying Your First Home, by Ilona Bray and Ann O'Connell (Nolo).

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