Why does mold show up in DC area homes?
Mold needs moisture, and the Washington climate provides plenty of it. Humid summers keep indoor air damp, especially in basements, closets and rooms with weak ventilation. Older rowhouses can have brick walls that wick moisture, leaky window wells, aging roof flashing and plumbing leaks inside walls.
Water events leave the biggest risk. General guidance is that wet materials should be dried within a day or two. If a flood, leak or sewage backup is not dried promptly, growth can start. That is why structural drying is the best protection. If a flood has already set in, see our page on flooded basement cleanup.
Condo and apartment buildings face another issue. A slow leak in a shared wall or from the unit above can feed mold in a place you cannot see until it becomes a smell or a stain.

