The Uraba coastal region in the Department of Antioquia, Colombia is conformed by consolidated sedimentary rocks of tertiary age and alluvial- deltaic deposits of quaternary age.Underground waters are of medium to high hardness and alkalines; they have elevated contents of iron and incrust the wells and piping.A saline intrusion push forward into fresh water in environs of Turbo. The salt-water pollution is caused by overpumping, and it is not commendable to exploit the surficial aquifer in that site.