Thanks a lot! Water is essential for all organisms and bacteria are not exceptions. Specifically, unlike large animals which mainly sustain its water supply by “drinking”, bacteria are so tiny that even just increased humidity or damp environment can encourage their growth significantly. They love it and do not get “drown”. 😉
We can also look at it in another way: because bacteria are so tiny and cannot move very fast, it’s hard for them to “search” for water. The way they “survive” in a damp environment might actually be only those bacteria which have access to a certain amount of water survive at last.