The ONEP is the most important operator in matter of production and distribution of drinking water because it assures close to 80% of the production and 25% of the distribution.
Created in April 3, 1972, the ONEP is charged of the following:

• Scheduling of the drinking water supply in the Kingdom,
• Survey, the realization and the management of drinking water adductions on the whole of the kingdom to the exception of those of the farming centers no delimited, and no endowed of a farming development plan,
• Management of water services in centers where this service can not be assured by the township it even,
• Technical aid in matter of surveillance of the quality of the food water when a public organism solicits it,
• Control, in link with authorities concerned of the water pollution susceptible to be used for the human feeding,
• Technical assistance to persons that solicit it for studies, the realization, or the management of the water system of adduction or distribution,
• Relevant assessments in link with the Ministry of the Public Health
• Relevant survey in link with Ministries involved in projects

Law n° 31-00 (Dahir n° 1–00–266 of September 1st, 2000) was adopted in the context of implementing the development strategy of sewerage services. Through this Law, the ONEP has been designated responsible for the management of sewerage services in communities, when the management of these services has been entrusted to him by decision of the respective Local Community Council. The Law has been preceded by similar decrees on the transfer of sewerage service management from communes to the regies.