G Grand Wisata area has a water treatment plant which aims in supplying clean water to the community who became the residence of that area. Grand Wisata water treatment plant has the capacity of 50 litres/second which has been expanded into 90 litres/second to supply a ±330 hectares area by taking raw water from Tarum Barat canal. In accordance with the plan to expand the residence area into ± 1100 hectares (100%) in the form of constructing the commercial area and new households blocks, it would require an extra water treatment plant. The plan off adding another water treatment plant will be constructed with a capacity of 210 litres/sec. Planning the plant unit refers to the design criteria, the evaluation result of the existing plant, data analysis result and the multi criteria analysis in order to determine the type of the processing units. Intake unit consists of bearer channels with gravity flow and is equipped with water gate and bar screen which leads into the collecting basin with a capacity of 54 m2. The aeration unit uses a cascade aerator type with an efficiency of 82.2%. The mechanical coagulation unit uses a trubine which is divided into another 2 units each with a capacity of 105 litres/sec and with a mixing power of 2,96 kW. Aluminium sulfate is used as a coagulant with an optimum dosage of 20 ppm. The hydrolisis floculation unit is divided into 2 units using vertical baffle channel type with a 124,7 m3 hexagonalshaped basin. The G value used is between 15 – 10/sec and 3254 seconds for time detention. The sedimentation unit is divided into 2 units with a basin shaped like a rectangular and with tubes settler. The capacity for settling zone is 190,57 m3. The inlet system uses manifold holes and the outlet system uses 2 gutters with v-notch and has a room for sludge with 88,48 m3 of capacity. Surface loading for the sedimentation basin is 100 m3/m2/hari. The filtration unit has 6 units of amount using rapid sand filter with 2 medias (sand and anthrasit) and gravel for buffer media. The capacity of filtration basin is 139,9 m3 and the velocity is 4,86 m/hour. The desinfection process is carried out at the outlet channel of filtration unit with a dosage of 1 ppm. The reservoir unit has 422,5 m3 of capacity. The headloss is 6,44 m. The total invesment for constructing the water treatment plant in Grand Wisata for 210 litres/sec of capacity is Rp. 3.358.482.125,00 or Rp. 15.9992.772,00 of litres/second. This total amount of money does not include the cost of operational and maintenance.