In this study, the conceptual design of a gravitational water vortex turbine has been developed. The conceptual turbine was designed to extract the energy from the house rooftop and generate the small power electricity using design principles. Through the concept of the House of Quality, the respondent requirements data were extracted to match with the scientific view in the design of the turbine. The data from the respondent was then linked to respond to the product characteristics by decomposing the function of the turbine. The divergence of three conceptual designs was being developed by cross-linking the part selection through the morphological chart. Of all designs, the final turbine design has been selected based on the concept of screening through the Pugh method and the concept of scoring of a weighted-decision matrix. Design 3 had been selected as the final product of this conceptual design study when the angle of the inlet opening is at 60°, the angle of pre-rotational is at 30°, with 3 number of blades, and when the body material is set as of polyvinyl chloride.