The prevalence of customary law within Arab societies, and in particular in the area of ​​water sharing and the organization of agro-pastoral lands has created a kind of conflict between customary legality and the positive law of the modern state, this the latter having become incapable of establishing its laws on the rural areas in which the tribes settle, and which have codified standards and have become familiar with modern laws enacted by the state.In order to preserve the social and economic balance in the Arab countries, the authorities in power were forced to promulgate laws and decrees in accordance with the customs and traditions of their peoples, in particular those related to agro-pastoral activity. Therefore, it can be said that the aim of the modern state is to place custom in a legal form respected by social groups.