In the early Middle Ages (fifth century AD to the fifteenth century AD), with the fall of the Roman Empire in the West, there were new areas like Gaul, Britain, Germania, Spain, Portugal and new socio-economic organizations that were consolidated in the feudal system. Water is understood as a vital element for economic development. Water wheels and mills were projected to provide driving force in grinding, weaving, dyeing and tanning, and manufacturing activity in properties of feudal lords.
The European population had a water daily consumption of only one liter by inhabitant. Water supply was made by direct river captation, different from the Roman practices to capture in long distances, bringing a regression from the sanitary point of view. The low consumption resulted in grave consequences to public health. With the economic, political and religious crisis, the practice of building walls and moats around the cities was adopted. With the fall of Rome, all knowledge was filed in religious monasteries and were only revealed something about sanitation in 1425, when Gian Francesco Poggio found the text written by Frontinus, titled “De Aqvis vrbis Romae” which contained teachings on hydraulics, sanitation and management, ignored throughout the Middle Ages.
The ownership of the water was redefined and fragmented in the hands of secular and churchmen aristocrats. Water ceased to be a public resource managed by the government, being managed collectively by citizens. Part of the daily household consumption was guaranteed by water purchase transported by carriers. Great part of the population used to dig wells inside their homes, which happened to become contaminated due to the proximity of pits and manure of animals, contributing to the progress of diseases in a period of major epidemics. Cholera, leprosy and typhoid were common in Europe, in addition to the Black Death, or bubonic, transmitted to humans by rat fleas, which infected half the population and wiped out about one third of the European population. In China and India the scenario was no different: over 23 million people have been were deceased in less than 12 years. Currently, there are about 2000 cases of black death annually worldwide, concentrated in areas where there are infected rodents.