The aim of the this paper is to survey and to evaluate the effects of Kocaeli Earthquake on the Water Supply and Wastewater Collection Systems in Sapanca and in Istanbul. Total number of pipe damages after August 17 was 400 resulting in the rate of pipe damage of 4.4 damage per km of pipe length for the asbestos cement type of pipe. Use of flexible pipes such as polyethylene, ductile iron and glass fibre reinforced plastic was recommended at the earthquake zones. Following the Kocaeli Earthquake rate of groundwater infiltration into the collector sewers of Tuzla Wastewater Treatment Plant has doubled. It was estimated that 6 to 12 million US Dollars is needed to rehabilitate the 180 km long water distribution network of Sapanca.