In order to assess the degree of pollution of wastewater from the city of M'rirt, we conducted during 2014; a study of physical and chemical characteristics of the waters of reference collector L6-Sp. it collects almost all wastewater from the city and is located right on the road to Meknes. The results showed that liquid waste is loaded into mineral matter in terms of electrical conductivity (Avg. = 3055,25?S / cm