Column leaching test has been found to be a useful tool to assess the mode of mobility of various heavy metals in soil, as well as the nutrients. It approximates natural conditions closer than any other laboratory test and at the same time yield more robust results than batch tests. According to several full scale studies, green roofs have been found to contribute to runoff pollutants. The aim of our study is to conduct column leaching test studying the impact of different substrates, height of substrates and type of drainage layer used in green roof establishment on quality of percolation, whether the soil mitigates or act as a source of pollutant, and its usefulness as tool for characterization of the impact of different establishing factors of green roof on the runoff quality. Different physico-chemical parameters are tested (POC, CODtotal, DOC, Heavy Metals, Total N, Total P and nutrients). In this thesis, we will detail various methodology, sampling method, analysis, results obtained, criticisms and finally future proposal of column leaching test and water quality of green roof percolation.