We are appealing for information after an incident at the University of Liverpool Guild of Students.
It was reported at 2.15pm on Tuesday 9 July that an offender entered a restricted basement area earlier that day.
It is suspected floor cleaner and body lotion was used to contaminate the water supply, and the University closed the building to allow for cleaning.
Community officers attended and investigations are ongoing.
Inspector Geoff Stewart said: “Thankfully suspicions were raised at an early stage and we do not believe anyone has come to any harm as a result of this reckless act.
“But it could have had much more serious consequences and we appeal to anyone who might have heard who is responsible, or anything about the incident, to contact police.
“If you saw anyone acting suspiciously in the vicinity of the Guild between midnight on Sunday evening and 2.15pm on Tuesday, we want to hear from you.”
Anyone with information is asked to contact Merseyside Police social media desk via Twitter @MerPolCC or Facebook Merseyside Police CC. You can also call 101 quoting incident reference 19100369445 or contact the independent charity Crimestoppers anonymously, on 0800 555 111 or via their online form at: https://crimestoppers-uk.org/give-information/give-information.