The Hanoi water distribution network has 32 nodes and 34 pipes organized in 3 loops. No pumping facilities are considered since only a single fixed head source at elevation of 100 m is available. The minimum head requirement at all nodes is fixed at 30 m. The set of commercially available diameters is [12, 16, 20, 24, 30, 40 inches].

The cost function is non-linear,

where
C is cost in dollars,
D is diameter in inches,
and L is length in metres.

The input file of the network is available in Epanet network solver format.