EpaCAD is a free software which easily converts an AUTOCAD file into an EPANET one, EPANET is the most widely used free software for simulation of pressurized water networks. EPACAD is able to automatically import the main properties of elements, largely providing the required information to build a network.
EPACAD can upload a .dxf exported from AUTOCAD. You will only have to select the layer (or layers) containing the pipes of your hydraulic model to start building your network. As other programs, you needn’t change your AUTOCAD file.
EPACAD is able to read X, Y coordinates of AUTOCAD files and also elevation of nodes (which are the ones describing your pipeline). So, you will get real lengths of your pipes and a reference of the current location of your items.
No matter how you draw your pipes in AUTOCAD, EPACAD reads both lines and polylines. Moreover, You can also create two nodes per line (regarding to initial and final node of the pipe) or, considering all the intermediate vertices of the latter in order to edit them later using EPANET.