During the last years, the over-exploitation of natural resources at lago de Tota and its watershed have affected the natural conditions of the lake, and thus, the abundance as well as the distribution of the wildlife which inhabits in the place. The aim was to design an evaluation tool of the environmental quality at the lake's shoreline zone, specially the one formed by the Egeria Densa, aspects like density, biomass, and macro-invertebrate functional groups of this plant were studied. The study was complemented by an environmental-variable analysis such the pH, electric conductivity, temperature, and oxygen diluted at 8 areas. An assessment system was designed, applied and validated, which integrates physical, chemical, and biological variables, as well as it consolidates 3 quality categories: low quality (Llano de Alarcón, Piscicol, and Los Pozos sectors), acceptable quality (El Túnel, Pispesca, and Hato Laguna sectors), and intermediate quality (La Playa, and La Custodia sectors). A multiple regression model allowed the valida- tion of the quality categories, with a 66%, at which the macro-invertebrate density was the most significant explanatory variable. This is a tool which provides input products for the permanent assessment of the environmental quality, as well as the environmental management plans of lago de Tota lake.