Water is one of the most important elements needed to sustain life. Some ancient civilizations struggled to maintain a constant supply of usable water, while others gained constant access, and those that did prospered. Nonetheless, these civilizations, whether they failed or succeeded, depended on water for drinking and irritating their crops; without it, they suffered from food shortages and famine. Ancient civilizations such as China, Egypt, Mesopotamia, and Rome were among those whose progress benefited from the successful cultivation of water. Although humans began as hunters and gatherers, once they gained the knowledge of growing their own food and domesticating plants, civilizations are believed to have formed, which then became dependent on agriculture and water. Water was the driving force of growth in ancient civilizations. A reliable source of water influenced the development of economies, guided religious opinions, shaped political and legal discussions, and influenced the advancement of technologies in several civilizations that shared a common bond, the need for water to sustain life. But we cannot look at “water” in a monolithic sense, because not all water can be used for drinking or irrigation. Usable water can be defined, in this case, as a reliable, constant source that is clean enough to drink or use for irrigation. This includes rivers, lakes, wells, but does not include oceans or contaminated water. In some circumstances, initially promising water can then become contaminated; Stagnant water in irrigation canals can become a breeding ground for mosquitoes and other disease carriers. Additionally, overuse or diversion of water can affect its quality, creating heavy water… half paper… a lot of flash flooding. This is in contrast to Egypt, which received even less rainfall than Mesopotamia, and was therefore totally dependent on the Nile for crop irrigation. The Nile River regularly overflowed, allowing for easy irrigation of the basin. Finally, Rome, unlike Egypt, grew up on the banks of a river, the Tiber, but the significant amounts of natural rainfall in the area made extensive irrigation for agricultural purposes unnecessary. Rome's main water problem was the lack of drinking water; the Tiber was often salty and unpleasant, which is why the Romans had to build aqueducts. All of these civilizations had a separate and distinct relationship with water, and therefore each had its own way of dealing with its conditions. Rooted in the conditions of water sources, reliable water has not only impacted the formation of economies but also helped them thrive..