EPANET is software, developed by Environment Protection Agency (EPA) of USA, for hydraulic modelling of water supply networks. It is a public domain software, free to download and use. The link for the download page is

EPANET download page.

It performs steady state as well as extended-period simulation of the hydraulic and water quality behavior within pressurized pipe networks.

It  provides an integrated computer environment for editing network input data, running hydraulic and water quality simulations, and viewing the results in a variety of formats. These include color-coded network maps, data tables, time series graphs, and contour plots.