The objective of this research was to evaluate the concentration levels of nitrates and sulfates in the surface runoff waters of the Huangamarca and Pollo micro-watersheds in Otuzco Pro^vince, La Libertad Region. Experimental studies of the water collected from surface runoff in the agroecosystems determined average nitrate concentrations of 0.214 meq/l and 0.662 meq/l in the Huangamarca and Pollo micro-watersheds, respectively. Sulfates ranged from 0.435 meq/l in Huangamarca to 1.321 meq/l in the Pollo microbasin. These values, according to the permissible levels, are below the contamination levels according to the water quality standards for irrigation. It is concluded that the waters of the Huangamarca and Pollo micro-watersheds studied are safe for use.