The concept of clean water has always been important all around the world. That concept was also important during bible times
At the time of Jesus, purity was extremely important, because it was emphasized in that Law of Moses. The Hebrew bible declares people ritually unclean for several reasons, those who have given birth, and those who have touched a corpse, and those with certain diseases for example. While some people might be declared unclean for their entire lives for common impurities, washing the hands or full emersion into clean water, was enough to make them ritually pure. This made water extremely pure in the first century world that surrounded Jesus.