This paper deals with the cost optimization of a pipe network using the technique of Genetic Algorithm. The software used for this purpose is WaterGEMS. Genetic Algorithm uses various factors for optimizing the cost and these factors depend upon the size of the network. An appropriate value of each factor is fixed by conducting sufficient number of trials and then a solution is obtained which gives the minimum cost.The method is first validated by a bench mark problem of two loop network given in literature. In the present study G.A. is applied for the cost optimization of a village pipe network of Budni block of Sehore district in M.P. (India) by changing the reservoir height. It is seen that the least cost of this pipe is attained at reservoir height of 19.4m.