This article aims to develop a working methodology to assess the application of the measures designed to avoid, reduce and, if possible, remedy significant adverse effects, included in the Environmental Vigilance Programmes. The study is based on a practical case study of the building project, currently under development, of a desalination plant located in the Spanish Mediterranean coast. A collection of measures was selected to be fulfilled in any building project of a desalination plant, and thus the requirements derivated from them. Their analysis will allow to establish the level of fulfillment (regarding to the measures taken from the Environmental Vigilance Programme or the Declaration of Environmental Impact) and the evaluation (regarding to the measures taken from specialized bibliography) of the indicators implementation. This monitoring provides the supervisor of environmental issues with a valid tool to negotiate with the developer certain modifications, with the objective of improving the effectiveness of the measures described in the Environmental Vigilance Programme.