I n the big cities in Indonesia the quality of the river water are above quality standards. Due to this matter the quality of water is decreasing. This is caused by industrial, office, and household waste that have been thrown into the rivers directly or indirectly. On the other hand the quality of the river waters in Jakarta is also influenced by the topography of where the river is located, mostly of which is relatively flat close by to where the dam is located. As a result, most of Jakarta rivers is flooded by other rivers from out of Jakarta.One way in order to increase the quality of water is by planting a certain type of waterplant named Eichornia crassipes and Pistia stratiotes. This is one of many effective and efficient ways instead of using chemicals, where in the near future may result to bad effects. In order for these plants to work effectively, they must pay special attention to controlling the plants.This research was done at two different levels, which was a introductory research level and a continuation level research. The purpose of this research was; 1) To know if the plant scan grow according to the water sample given. 2) to know if it needs an extra approximating level for the plant in the next level 3) To estimate the time needed for this research. This research used 6 variables (P) and was done twice. Water samples were taken to be analyzed every two days (td = 2 days) and also every 4 days (td = 4 days). Water samples where taken as much as 50 ml from the experiment bucket. Resources from tnis sample was taken from the river water at Grogol, by the dams that is located by JI. S. Parman, West Jakarta. The parameters that was used was COD, Ammonia, Dissolved Oxygen, Fe stone and Mn. This research was done to know how the plants influenced the decreasing of the chosen parameter and also the decreasing of the infected concentration per plant weight. At the introductory level of research , the results showed that there was no need for a approximating level because the plant was able. to grow fairly good physically at a composition of 100% water sample, which then both plant was used for next level of research. The largest effect that the ammonia concentration remove was by the E.crassipes plant. After 8 days (with 4days left) it was 72 %. In order to reduce the COD concentration that was in the P. stratiotes plant with four days left of the experiment resulted to 62 %. The level of dissolved oxygen within the P. stratiotes plant with 4 days left of the experiment was 3,7 mg/It (at 12th day of experiment) The level of Mn stone in the E. crassipes plant with 4 days left of the experimentwas 81 % (at 4 day of experiment). Lastly Fe element that was contained in the E. crassipes plant with 4 days left of the experiment was 63 % {at 4th day of experiment).Based on these observations we know in order to treat a E. crassipes plant with 4 days left is very effective to increase the quality of the level. This has proven to increase three (3) different infecting parameters that was used in research, compared to the Pistia stratiotes plant. Lastly this experiment has the highest effectivity within 4 days of experiment.