The Omerli dam is the major drinking water reservoir of the Istanbul Metropolitan City. Its basin area experiences a rapid increase of the urbanized area and updated information is needed to assess and manage the impacts of land-use changing on water quality. Results of increasing rapid population are unplanned and illegal housing, irrelevant industries and motorways passing through the protection zones of the catchments, area, together with insufficient infrastructure. One important drinking take is taken as study area for this paper. The study is focused on the assessment of urbanization in relation to land-use and water quality using Remote Sensing and GIS techniques for all protected zones of the Omerli Water Basin Area, and a time variant analyzing model is obtained. The project uses SPOT-PAN, XS and IRS-1C/D PAN and satellite data of 1992, 1996 and 2000 for urban analysis, as well as LISS-III satellite data of 1996 and 2000 for water quality. For calibration and validation, ground truth samples are collected from the. experimental area.