The Tilata Formation, with unconsolidated permeable layers, in the Bogota Sabana, are aquifers with important yields, relatively easy to drill. To know its lithology is useful for hidrogeological purposes. Two lithological colums of two water wells are presented. Its electrical resistivity ranges from 20 to 70 Ohm.m. The wells from the Tilata Formation could have specific capacities of 6,6 LPS/m. The transmisivity could be larger than 900 m2/day. The storage coefficient ranges from 2,2xlO-3 to 5,6x1 04 in the two pumping tests, carried out with one observation well. Notions of well hydraulics are given in order to educate the ground water users, about hydrogelogic basic principles.