"The San Juan Bautista Londó aquifer, with an extent of 593 km2, is the major source of potable water for the City of Loreto. The San Juan Bautista Londó Basin was an important agricultural area in the seventies but despite overexploitation, a significant reduction of agriculture activity took place. Previous studies indicated that the composition of thermal water in Concepcion Bay, Guaymas Basin vents, and deep circulation water from Las Tres Virgenes near Santa Rosalia show little variation. Their composition and typical ocean water were compared to water samples from different wells, located in the San Juan B Londó watershed. Based on cluster analyses, five different groups of groundwater were separated which represent seawater, the geothermal end-member, groundwater with a stronger geothermal component, groundwater with a certain geothermal influence, and groundwater without a geothermal influence."