The first thing most people tell us when we show up to their house is, They wiped down the mold with bleach so they don’t understand why it came back.
Bleach doesn’t kill mold and in fact on non pourous surfaces actually feeds it. To understand this you most first understand mold only needs two things organic material to grow on and water to live. So when mold finds its way onto wood or dry wall it isn’t just on the surface of this material it is deep into the grain of it. So when you start adding bleach which is 90% water you are only discoloring and removing the surface layer of mold while giving it more water to live off of.
Below is a full article explaining all the reasons why bleach is bad for mold.