By studying history, we find that Iranians had discovered the flow of groundwater three thousand years ago, and considering that groundwater in the central parts of Iran is mostly salty and unusable for drinking and agriculture, groundwater from the aquifers of the mountain slopes has been transported to the edge of the deserts by the force of gravity, and has made the deserts habitable. Another thing is that the art of building aqueducts was invented by Iranians, and other countries have gradually followed suit. One of the characteristics of these aqueducts is that they are still usable after three thousand years and even until the last two or three decades they have supplied seventy-five percent of the country's water needs. The results of the present study, which was conducted using a descriptive-analytical method and the sources were collected using a library method, indicate that the duties of the water law are to protect water in its natural form and other forms such as flowing water, stagnant water, groundwater, etc. from damaging attacks and to maintain water resources.