Officers, including search and rescue teams and the police helicopter, were involved in the search which is now believed to be a prank.
A large number of emergency services workers rushed to the scene just off the A51 in Rugeley on Thursday evening.
Crews carried out an extensive search using fire and rescue boats, but did not find anyone in the water.
Police now believe it was a prank involving a number of youths causing members of the public to call the emergency services.
Staffordshire Police have now launched an investigation.
PCSO Chad Carrington said: "A large number of emergency services vehicles and personnel including the police helicopter have been in attendance to reports of a person in the water off the A51 in Rugeley yesterday evening.
"An extensive area search has been carried utilising a police helicopter, fire and rescue boats and persons on the ground from various services, however with negative result.
"Whilst unconfirmed, intelligence is now suggesting that this was a prank involving a number of youths causing members of the public to call, fearing the worst.
"An investigation is now underway to establish further details. As you can imagine this incident placed a massive amount of pressure on the emergency services so we are keen to find answers."
Anyone with information is asked to call Staffordshire Police on 101.