EPANET, adjusted to build with autotools.
You can use OBS to build EPANET for various Linux distributions:
https://build.opensuse.org/package/show/home:sdteffen_de:epanet2/epanet2
To cross-compile from Ubuntu for 64bit Windows:
sudo apt-get install mingw-w64 ./configure --host=x86_64-w64-mingw32 make make install-strip
Please also have a look at epanetl, a localized version of EPANET: