Mold

Clean Up Safely After a Flood

Flood water may contain bacteria, petroleum and chemicals. Mold can grow in a flooded home that is not properly cleaned and dried out.

Learn how to safely clean your home after a flood:


Mold (mildew), mushrooms and yeast are all types of fungi. Fungi are found both indoors and outdoors. Hundreds of different kinds of mold are commonly found in the United States and New York City.

Exposure to mold can cause or worsen asthma symptoms and allergies, such as hay fever. People who are allergic or sensitive to mold may experience congestion, runny nose, coughing and trouble breathing.

Some people are at risk for more severe reactions to mold, such as fever and shortness of breath. This includes people who are exposed to large amounts of mold at work such as agricultural workers and building demolition workers. People who have had or are undergoing certain medical procedures, such as bone marrow or organ transplants and chemotherapy, are also at risk. Health symptoms usually disappear after the mold has been removed.

Identifying Mold

Mold can be different colors, including gray, black, green, yellow and orange. It may look furry, slimy or powdery. Some mold has a musty, stale or earthy smell.

Mold usually grows in wet or damp places. It can grow on paper, fabric, wallpaper glue, sheetrock, wood, soap scum, leather and other surfaces. It can grow where there is water, high humidity or damp conditions. Mold grows faster in warm temperatures and high humidity.

Exposure to Mold

You can breathe in mold particles if mold is disturbed or damaged. You can also breathe in tiny spores (similar to seeds) that mold may release into the air. Mold can get on your skin if you touch it. You can swallow mold if you eat moldy or spoiled food. If you think that you have symptoms related to mold exposure, you should see a health care provider.

Mold Prevention and Removal

The best way to prevent mold is to remove water and moisture sources.

  1. Fix leaks. If you are a tenant, report the problem to your building manager.
  2. Dry out wet and damp areas like bathrooms, kitchens and basements. You can monitor humidity with a humidity monitor from a hardware store.
    • Use an exhaust fan that vents to the outside while cooking or bathing.
    • Open windows to let in fresh clean air from outside.
      • Only open windows when outdoor air pollution is low. If you live near a high-traffic area, consider where windows are located before opening them. Go to Airnow.gov to check air quality in your area.
      • Make sure window guards are installed if a child younger than 11 years old lives or spends time in the home. Screens are not a substitute for window guards.
    • Use a dehumidifier or air conditioner to help lower indoor humidity.
      • Run your air conditioner on ‘recirculation’ mode on bad air quality days so it does not bring in air from outside.

To safely remove mold:

  1. Keep children and pets away until area is cleaned.
  2. Use water and soap (or dish detergent) to clean mold on walls or other hard surfaces.
  3. Wear waterproof gloves while cleaning.
  4. Dry the cleaned area completely.
  5. Wash and dry (or throw away) sponges or rags used to clean mold.

Also see: CDC Infographic: 8 Tips to Clean Up Mold.

If the mold returns quickly or spreads after cleaning, there may be an underlying problem, such as a water leak. Report the mold problem to your landlord.

If the problem isn’t fixed in a timely way, or if the mold is in a non-residential location, submit a complaint online or call 311.

If large areas of mold are present, you may need outside help such as a professional mold abatement company. Be sure your contractor is licensed and follows NYS Labor Law requirements.

Building Requirements

Landlords of buildings with three or more apartments, or buildings of any size where a tenant has diagnosed moderate or severe persistent asthma, are required to keep tenants’ homes free of mold. This includes safely repairing underlying problems like water leaks.

For more information on controlling and removing mold hazards email NYCHNP@health.nyc.gov, or call 311 and ask for the "Healthy Neighborhoods Program."

Additional Resources

More Information