So the woman left her water pot, and went away into the city, and said to the people,

 John did not invent the title. In the Old Testament God had often been called the God of salvation, the Saviour, the saving God. Many of the Greek gods had acquired this title. At the time John was writing the Roman Emperor was invested with the title Saviour of the World. It is as if John said: "All that you have dreamed of has at last in Jesus come true." 