Attention has been rising towards natural water purifying agents as the effect on human health and the environment of synthetic chemicals became evident. Maerua sucordata has been used as a natural coagulant traditionally by rural communities living around Omo River. This study focused on the coagulation properties of Maerua subcordata powder and its effect on bacteriological properties of water. The powder was prepared by cutting the root into pieces, drying on sunlight, crushing by traditional mortar and pestle, and finally ground by traditional mill and sieved. The optimum dose was determined by jar test using turbidities 500, 370 and 240 FTU. The workable turbidity was 370 FTU; with which further tests were made. The powder was used to treat water with known turbidity as a primary coagulant and also with alum. Its efficiency was compared with alum and Moringa. The powder, when used alone decreased the turbidity of water from 370 FTU to 8 FTU upon 1 ½ hr settling, while Moringa achieved 9 FTU. This was much lesser compared with alum. When used in combination with alum, 1:1 mixture reduced the same turbidity to 6 FTU and 2:1 ratio of alum to Maerua produced 8 FTU with the same settling time. Maerua powder can give best results, i.e. in the WHO guideline range, upon longer settling time. On the contrary, turbidity of the water treated with Moringa powder had regained upon longer settling times. Maerua powder was effective at moderate turbidity. The effect of Maerua subcordata powder on bacteriology of the water was insignificant. Only 66.7 % reduction in fecal coliform count was observed. Key words- Maerua subcordata, jar test, residual turbidity, turbidity, bacteriological quality, total coliform, fecal coliform.