Facing this file calculation of a system of water supply using the standard of manning; you should emphasize that the theories on in hydraulic and darcy hazen williams and hazen williams is a trend or approximately 0.001. entered number of lots a project; number of people per lot and water supplied daily analysis determine if this system is correct or not projecting variation between the maximum and minimum speed is in the range of 3.00 to 5.00 m / sec .