A A design of Water Supply main distribution network of Pondok Ungu water Treatment Plant covering 11 Kelurahan spreaded in Western Bekasi, Northern Bekasi, as well as Southern Bekasi.The design is decided into two implementation design phases, at the end of the Phase I it is estimated that 43% ( or equal to 237048 population ) shall be covered by the service. Further, at the end of the Phase II, 60% ( 460215 population ) shall be covered. It is estimated that total water demand at the end of the design phase is 2380.88 1/s.The design cover in implementation of aloop type distribution network in Pondok Ungu Treatment Plant. This was made based on the consideration that the distribution of the population, as well as the city development of Bekasi will be happined in such a direction. Regarding the material of the pipe it has been assumed that PVC pipes will be used, ranging in diameter from MM to 950 min, with a total length of 37321,5 m.Further, consedering of a flat type topographical with almost without hills city contour of Bekasi, it has been assumed that the distribution of water will be implemented by using of pumps, of which GAE ETA-N Low Pressure Centrifugal Pumps of 50 cps, n = 1450 rpm has been refered. It is estimated that at the end of the design year they will be using 32 units of such a pump connected in parallel. The pumps theyself were characterized 300 m3/hour, 260 m /houyr and 200m /hour in capacity, 60 m in head, at the efficiency of 79%, 77% and 75%, bringing power of 62 Kw, 45Kw and 45 Kw respectively.Finally, it is estimated that based on the current situation, the total cost to cover all supplies, constrictions and design of these main distribution network is Rp. 44.745.255.270,00