1. A method for detecting leaks and locating leak spots in a fluid distribution network, the method comprising: calculating value of non-revenue fluid; receiving data corresponding to pressure from pressure sensors in the fluid distribution network; receiving data corresponding to flow from flow sensors in the fluid distribution network; estimating pressure values at the pressure sensors; estimating flow values at the flow sensors; comparing received data and estimated values of respective sensors for corresponding time periods; detecting existence of leak in the fluid distribution network, if the value of non-revenue fluid is above a certain threshold; and locating one or more leak spots, if a leak is detected, by solving an optimization problem.