I need some knowledge on the legal side

Iv been selling some here and there for the past month. Not alot but enough I guess. Today I look go outside to get in my car and there is a dea and fbi raid at a house across and down the row from me. Didnt know those guys but there were a little younger and college students.
Sad part about it is I never notice surveillance in my neighborhood. Its a townhosue community so maybe thats why(been here 8 months). Not sure if this makes my place hot or not. But I dont do very many deals here so i think im good.
What I want to know is how to stay under the radar and what the cops need to search a house. Dont they have to have probable cause, like someone wearing a wire or something? Or like see drugs or something. Can they just knock on my door one day and come in on "a hunch?"
Not sure if posting here can be traced back to me so i might delete this account.

no they need reliable info to search and u r to paranoid chill
did u sell to anyone at that house if not it is unrelated
dont delete account u r safe if u dont post personal info

be careful who you sell to cause if they bust your buddy and ask him where he gets it from if he points u out they will set him up to go buy more weed from you with there money and thats there probable cause

Naw, I never talked to them before. And I highly doubt we have the same customers. Maybe I was a little too paranoid about the whole thing. I guess id like to know what is considered "reliable information". The term is somewhat vague.