In addition to the EPA information, I've found that if moldy materials are removed (carpet/sheetrock/etc), and the water source is remedied so moisture is no longer getting into the home, it clears up very well. If the home is very tight, installing an air exchanger or some sort of apparatus to get air flowing through the home helps. Also, for mildy moldy sheetrock and hard surfaces, you can spray the moldy areas with bleach and clean, and if the area stays dry, the mold should not return. Hope this helps!
RE/MAX Today's Realty