The problems associated with water loss are numerous. High real losses indirectly require water suppliers to extract, treat, and transport greater volumes of water than their customer demand requires. The additional energy needed for treatment and transport taxes energy-generating capabilities which often rely upon large quantities of water in their process. Leaks, bursts, and overflows often cause considerable damage and inflate liability for the supplier.The main objective of the current research is to find the direct relationship between the losses in water distribution networks and the residual chlorine. The experimental program is designed to monitor the losses in water distribution networks and how it can be related to the residual chlorine in a certain part of an existing network. For this purpose, a certain measurements on a part of a water network in Nasr-City, Cairo, Egypt have been made to find residual chlorine relationship with time and pipelines lengths and amount of leakage. The field measurements of both the rate of flow and the value of the residual chlorine at different locations and at consecutive intervals of time were carried out through three steps (runs). The first run for a single pipeline, the second step for three pipelines while the third run for the whole part of the network (nine pipelines).Two main equations are concluded from this field measurements and analysis. Equation (1) represents the relationship between residual chlorine, time and pipeline length, and equation (2) represents the relationship between residual chlorine and leakage with pipeline lengths. The results from these equations verification showed that, deviation percent between field measurements and the application of the equations is minor and within allowable rate.

The objective of conducting this research is to find a relationship between leakage and chlorine added in terms of measured values of pressure, the length of pipe, age of the network and type of pipe for eight different zones in Cairo water supply network. To achieve this goal, the measured values of water leakage, residual chlorine, pressure, length of pipes, age and type of pipe within the eight networks have been sorted out. By using linear regression analysis, the equation that represents the relationship between the independent, (residual chlorine) and the dependents, has been obtained with acceptable error. The application of the equation of Hazen -Williams was applied for taking the effect of p ipe type & age using its friction coefficient on pipe length and then pipe diameter using the flow. Then the lengths were combined with all other data for each network, to get the relation between leakage and residual chlorine. By applying the Program SSPS 10 for windows on the data determined from the field measurements from zones 1,2,3,5 & 8 it produces an equation simulate the leakage value relation with the residual chlorine taking into consideration the pipes diameter, length, age and type with the pressure loss in the studied networks. The produced equation verified with the field measurements from zones 4, 6 & 7 and was successfully applicable with error less than ±10%.