Highlights: Water Treatment Plant sludge is a residue consisting of metals, such as aluminum, from the coagulants used in the process. Aluminum can be responsible for environmental impacts that cause symptoms of toxicity in vegetables, such as greens, and are also used as indicators of the presence of this element in the environment. Aim: Thus, this study sought to analyze the possibilities of using lettuce, Lactuca sativa L., as a bioindicator of environmental contamination by aluminum from the sludge generated in Water Treatment Plants. Design/Methodology/Approach: For this, a weighted analysis was performed that considered qualitative and quantitative parameters for the determination of the ideal bioindication, in which weights and grades were assigned to the aspects related to lettuce characteristics, comparing the sum to values presented in studies that used the same methodology. Results: In the weighting performed, it was observed that the sum of the scores presented in relation to the parameters of ideal bioindication for lettuce was quite satisfactory, with values close to and higher than those observed in other studies. Practical Implications: From this, it was possible to analyze that lettuce presents a potential use in bioindication of environmental quality, mainly for environmental impacts by metals, such as aluminum, present in Water Treatment Plant sludge. Originality/value: Therefore, this study contributed to the understanding regarding the good performance of lettuce in the identification studies of the ideal bioindication and the characterization of the species as a good bioindicator of environmental quality, as well as the fact that bioindicators are essential elements for the evaluation of tolerance levels related to possible effects from environmental pollution. Research limitations: It is assumed that field studies and laboratory analyses can prove the aspects evidenced here, especially the ability of the vegetable to indicate environmental impacts by metals present in the Water Treatment Plants (WTP) sludge, in this case, aluminum.