Mold in My Home

How do I know if I have a mold or moisture problem?
Mold or moisture problems may be visible or hidden. Visible areas could include surfaces in the building itself and items in the building. Examples of hidden problem areas include beneath wallpaper, behind furniture, behind baseboards, or inside walls, floors, or ceilings. Signs of a mold or moisture problem in your home are:

• Water-stained, discolored, or moldy surfaces
• Water damage, such as warped floors, peeling or bubbled paint, or rotting wood
• Damp surfaces, including condensation on windows or walls
• An earthy, musty, or moldy smell

You might also have a mold problem if people who are sensitive or allergic to mold have symptoms when they are in your home.

What are the main steps to fixing a mold or dampness problem?
There are several steps to fixing a mold or dampness problem.

• Find the damp or moldy areas
• Fix the source of the moisture problems
• Dry or replace wet materials
• Clean or remove moldy materials

Further information can be found on our Factsheet “Mold or Moisture in My Home: What Do I Do?”

What are the most common sources of excess moisture?
Excess moisture can come from either indoor or outdoor sources. Indoor sources include:

• Leaking or burst pipes
• Insufficient venting where water is used (for example, bathrooms, laundry areas, and kitchens)
• Condensation on cold surfaces

Outdoor sources include:

• Water intrusion (leaky roofs, leaky windows) and flooding
• Outdoor surfaces that slope and drain water toward the home
• Sprinklers and downspouts directing water at the house

I smell mold, but I don’t see any — How do I find the mold or moisture problem?
You are right not to ignore mold odor, because this is one of the best indicators of potential health risks from dampness or mold. If you cannot find the mold or moisture problem, you may need a general contractor experienced with water damage assessment to find the source of the mold odor. Thorough mold investigations may require some damage to building materials to find mold or dampness in hidden spaces. We do not recommend testing for mold [see section on Testing for Mold].

What materials can I effectively clean of mold and what should I remove?
Generally, materials are either porous or non-porous. Non-porous materials (such as glass, plastic, metal, or ceramics) do not absorb water and can be effectively cleaned of mold [see next question]. Porous materials (such as drywall, ceiling tiles, drapes, or upholstered furniture) do absorb water and usually cannot be effectively cleaned of mold. If the porous materials look or smell moldy, they should be removed. In addition, porous materials that have stayed wet for more than a day or two may need to be removed, even if they do not yet look or smell moldy, because mold may have started to grow under some conditions.

How do I safely deal with moldy materials?
If you are sensitive to mold or if the amount of mold is large, consider having another person or professional do the work. Use personal protective equipment, such as goggles, gloves, and an N-95 particulate respirator. A “dust mask” will not protect you from mold. It is also advisable to wear removable protective clothing (such as disposable suits) while handling moldy material, as mold can collect on clothes and be released later. It is important to prevent contamination from spreading from the source area to other areas in the home [see guidelines below]. It is also a good idea to ventilate the area you are cleaning to the outdoors during and after the work.Cleaning non-porous materials:
Scrub non-porous materials thoroughly with soap and water to remove mold. We do not recommend using bleach or products that contain bleach. Bleach can be a respiratory hazard and disinfection is not necessary if you have cleaned the material thoroughly with soap.Removing porous materials:
Moldy materials should be sealed in disposable bags or wrapped in plastic and disposed of as normal trash. The moldy material does not need to be treated as hazardous waste.
The US EPA offers further tips and techniques for cleaning up mold in homes.