The issue of water is gaining Egypt's attention in recent times, especially after the start of the Ethiopian Dam and Egypt's entry into the era of water poverty, where water is considered one of the most important natural and environmental resources. Moreover, the constant pursuit of increasing development rates, Wherever the residential building sector acquires a large proportion of water consumption between different activities. The research aims to rationalize water consumption in residential buildings by developing water supply and drainage systems responsible for distributing water within various units and spaces. Consequently, the research focuses on water treatment and the integration of water reuse techniques within residential buildings. The research studies a repeated porotype of economy housing in new cities in Egypt. The study surveyed number of users of the same levels to get the water consumption rates per unit. The research finds that water consumption can be reduced by 30.4% in residential units by modifying water supply and drainage systems design Which is reflected in the cost savings. In addition, the cost of proposed system can be returned within 2.5 years comparing to the savings cost.