EPANET is described as 'Developed by EPA's Water Supply and Water Resources Division, EPANET is software that models water distribution piping systems. It is a Windows 95/98/NT/XP program that performs extended-period simulation of the hydraulic and water quality behavior within pressurized pipe' and is an app. There are nine alternatives to EPANET for a variety of platforms, including Windows, Linux, Web-based, Android and iPhone apps. The best EPANET alternative is pfcalc, which is both free and Open Source. Other great apps like EPANET are WaterCAD, Fluid Network Studio, PIPE-FLO and InfoWater.