Building Dampness and Mold

In 2009, 9.9% of U.S. homes had water damage from exterior leakage, while 8.1% had water damage from interior leakage based on data from the American Housing Survey of the U.S. Census. However, the survey did not cover dampness or mold. There is otherwise no national database on the prevalence of dampness and mold in U.S. houses; however, compiled data from studies that reported prevalence of various moisture-related conditions in U.S. houses. There is considerable variation in the prevalence estimates for each of the indicated moisture categories. For the “any dampness or mold category”, four of the studies report the prevalence to be 50% or more, while three report prevalence values below 50%. The largest study (Spengler, 1994) reports prevalence of dampness and mold in 50% of the homes. Excluding the Freeman study because it only included bathrooms, the population weighted average prevalence of dampness or mold from these studies is 47% in the U.S.