Water distribution system (WDS) is an essential component of the entire water
supply systems. It represents a vital component of the urban infrastructures that requires
significant investment. The basic hydraulic equations describing any WDS are non-linear
algebraic equations which must be solved iteratively. Genetic algorithms (GA) are currently
one of the state-of-the-art techniques for the optimization of engineering systems including
water network design and rehabilitation. They are capable of finding near optimal cost
solutions to these problems given certain cost and hydraulic parameters. In this study, an
anonymous WDS in Egypt has been selected and designed/rehabilitated using GA under
deterministic conditions as single objective and as multi-objective problem. The obtained
solutions were compared to the results obtained from the ordinary design using non-optimal
methods. Results indicated that GA capable of obtaining a robust WDS with least cost. Multiobjective
solution that includes robustness or water quality objective as the 3rd objective
could be obtained giving the trade-off curves of the WDS.