Harvesting the numerous small scale hydroelectric potential is a way to increase the sustainable hydraulic energy production in developed countries. The condition to meet economical profitability with pico power stations - below 25 kW - is to minimize the required capital expenditure while maximizing the efficiency of the installed power stations. It requires developing dedicated technologies. This paper deals with the design of a standard counter rotating micro-turbine with custom runners to harvest picohydro potential on water utilities. The turbine's runners are tailored according to the characteristics of the installation site to maximize the efficiency. An automated tool path generation algorithm has been developed to cut the recurring costs usually associated with custom free-form components such as the runners.