Samples of lettuce, soil, and irrigation water from city gardens located in Bogota were analyzed in order to detect and quantify lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni), arsenic (As) and mercury (Hg). Metal concentrations of the soils and vegetables varied according to urban garden location; all detected metals in the soils and the lettuce were below health-based guidance values (local and international standards); heavy metals in irrigation waters were not detected; soils, metal concentrations of the irrigation waters and lettuce did not correlate. It means that urban agriculture should not represent a significant chemical risk for the consumer’s healthcare due to the possible intake of heavy metals and trace elements. However, it is necessary to continue conducting research on this important topic that is directly related to food security and food sovereignty and that will add information to update and establish a basis for reference levels regarding heavy metals in water, soil and vegetables.