: What are the requirements for placing a backflow preventer on a water service connection to a sewage pumping station in an underground vault?Get a fully licenced contractor, who is licenced in backflow prevention to look at it, if you get the sewer back into the potable water you are screwed.DISCLAIMERAll advice is given with-out seeing the job, and hence all advice MUST be taken as advice with limited knowledge on the exact situation. NO responsibility can or will be taken. And yes, I am a licensed plumber with my own business in Brisbane Australia