No one wants to buy a house with a mold problem. Unfortunately, these spores are not always easy to detect. Learn how to detect mold in homes you are looking to buy, get the seller to disclose mold issues, and negotiate around any mold problems that come to light during the sale. 

Mold is a fungus that comes in various colors 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), but can survive in almost any damp location. 

Common places you will find mold in a home:

  • around leaking pipes, windows, or roofs 
  • basements or other places that have flooded and haven’t 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.

Mold presents an ugly appearance (black, white, green, orange, purple, or gray in color) and sometimes an unpleasant odor. Mold can also 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.

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.

How to Detect Mold in Your Basement or Home

  • Be on the lookout for mold. When you are thinking about buying a home, look for the elements above to find any obvious signs of mold. Look for standing water in the basement, water marks on walls, or musty smells (usually in bathrooms, kitchens, laundry rooms, basements, cabinets with plumbing, or other areas with plumbing). Find out whether a newer home 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. Your home inspector may see obvious signs of mold or water damage if you have the home professionally inspected before you buy it. Most home inspectors will mention obvious signs of water damage and the possible presence of mold. The inspector may also check spaces you might not; they may see things you would not. Ask whether the inspector saw signs of mold or potential mold dangers and ask that these results be included in the inspection report. 
  • Ask the seller to disclose any mold or water-related problems. Some states require sellers to disclose information about mold. It is the seller’s duty to disclose only things they know about or reasonably should know about. They do not have a duty to go look in the walls to see if there’s mold, for example. You can still ask for such disclosure in states where mold disclosures are not required. In addition, ask questions about things that could lead to mold growth, like “Have any pipes ever burst?” or “Have any of the windows ever leaked?”
  • Listen to agents and appraisers. Real estate agents or brokers have a duty to disclose problems they know about in some states. An appraiser should also notify you of any signs of a mold problem if it could affect the value of the property.
  • Add a mold-related contingency to your offer. 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 is not usually necessary when it is visible on surfaces. Most people will end up relying on the detection methods discussed above.

Should You Buy a House With Mold Problems?

You will want to be especially concerned about limiting exposure to mold If you or a family member has asthma or if a baby or an elderly person will live in the house. Decide whether the cost of removing the mold and fixing the source — both in time and money — is worth the price you will pay. If you have an inspection contingency and the mold is revealed as part of the inspection, or if you have a specific mold contingency, you can ask the seller to reduce the asking price, to fix the problem, or you can choose to walk away from the deal.

What If The 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 may be liable to you for failure to disclose. 


The U.S. Environmental Protection Agency (EPA) provides extensive information in the Molds and Moisture section of the EPA website. The Centers for Disease Control and Prevention (CDC) also has useful resources on mold on its website. Most of the mold-related regulations occur at the state level. Check the state agency responsible for mold and indoor air quality. You will find links to your state agency (often the department of health) and resources on the EPA site. The National Conference of State Legislatures (NCSL) has an Environmental Health Legislation Database that tracks state legislation on environmental health hazards, including mold.