An experimental study was performed by using the world standard treated drinking water of the city of Ankara. Chlorine is known to be consumed in the bulk liquid phase and at the pipe wall. In the present study the bulk decay pattern was investigated in the absence of pipe wall decay. The test results presented describe how chlorine bulk decay might change with the travel time (residence time) of water in a pipe and the temperature of water in the network. Other than the single constant bulk decay coefficient of chlorine for the first-order exponential decay equation frequently used in many previous studies and models, a parameter coupling residence time of water might be more representative for the water of a city supply network. The test data also showed that chlorine decay of stagnant water in bottles does not differ in magnitude from that of flowing water in a pipe. Additionally, the test results reveal no correlation between initial chlorine concentration level and the bulk decay pattern. (C) 2018 American Society of Civil Engineers.