Tourist resorts have been planned for years without taking into account sustainable development and therefore without a previous study of the economic, social and environmental impacts produced in their influential areas. This work is centred on the latter; to be exact, it is focused on the management of water and energetic resources. After an extensive research of information and regulation currently inforce, a spreadsheet is developed, an interactive tool to be used in the design process of any resort or tourist development. Although the weather and other territorial data introduced by default are from regions of Spain, the user can apply the methodology in other countries introducing specific information of the area. To start the evaluation, the user has to introduce some characteristic parameters of the resort. The spreadsheet then provides graphical and numerical results. The water analysis proposes a balance of water flows and makes a simulation to see if the resort could water green areas with recycled water, which comes from treated wastewater. The energetic analysis works out the energy savings by using both photovoltaic and thermal solar energy and estimates the reduced emission of CO2. As a result, the methodology provides theoretical values and for esees the possible failures of the system so that the user could correct them before building the real resort .