The practice of intensive farming in Guasave Sinaloa, Mexico, promotes the application of high amounts of fertilizer in vegetable crops and grains, nitrates are the best known inorganic contaminants, they pollute ground water, and are perhaps the ones of most health hazard. The concentration maximum of nitrates in drinking water recommended by the official Mexican standard (NOM) is 10 mg L-1 of N-NO, levels above this value should be of concern for their possibledetrimental effect on human health, mainly by reducing levels of oxygen in blood (methemoglobin). The main objective of this work is to analyze the levels of nitrates in drinking water in communities of Guasave Sinaloa. The analysis was performed using two methods: the Standard Test Methods for Nitrate Ion in Water and the Merckoquant Nitrate Analysis Method. The results show that nitrate concentrations in public drinking water networks and treatment plants is abovecritical levels (10 mg L-1 de N-NO3) in different communities; the highest concentration was in Bamoa Station (22.7 mgL-1 of N-NO), known for its horticultural activity with concentrations up to NOM-127-SSA1-1994.