In this study several tests were conducted to investigate the possibility of re-use the filter backwash water (FBWW) by re-introducing it with raw water (RW) for treatment. FBWW in water purification plants is being thrown into sewage plants without any benefit. The amount of wash water generated estimated at a rate of (10-15%) of the amount of purified water in the plant. The treatment of Backwash water depends on the need for re-use, either for drinking or for irrigation purposes, depending on the compliance with the standards in the water quality specifications. The FBWW resulting from Giza water plant have been analyzed scientifically and mixed with RW at different ratios (from 10% to 50%). The results of experiments showed that the best mixing ratio was 40% FBWW to 60% RW, also the economic feasibility of water reuse have been discussed.