Clean up mold! Mold can cause serious health problems. Dry indoor areas and discard anything wet over 24-48 hours.
Fix leaks and seepage. If water is entering the house from the outside, your options range from simple landscaping to extensive excavation and waterproofing. (The ground should slope away from the house.) Water in the basement can result from the lack of gutters or a water flow toward the house. Water leaks in pipes or around tubs and sinks can provide a place for biological pollutants to grow. Put a plastic cover over dirt in crawlspaces to prevent moisture from coming in from the ground. Be sure crawlspaces are well-ventilated. Use exhaust fans in bathrooms and kitchens to remove moisture to the outside (not into the attic). Vent your clothes dryer to the outside. Turn off certain appliances (such as humidifiers or kerosene heaters) if you notice moisture on windows and other surfaces. Use dehumidifiers and air conditioners, especially in hot, humid climates, to reduce m...