This paper aims to present the water quality index (WQI) made in the pond of the UNIVAP's treatment plant. Water quality index (IQA) is a classification parameter that can be obtained from the São Paulo State Sanitation Company (CETESB), which presents the optimal, good, regular and very poor classifications for each water course, lake, pond or river analyzed. The physical, chemical and biological parameters were compared to those stipulated by CONAMA Resolution 357/2005. [ABSTRACT FROM AUTHOR]