With rapid increase in population, industrial development and water usage, faecal pollution of drinking water is creating enormous public health hazards like water born diseases due to careless disposal of sewage water [1]. Drainage of sewage water without treatment and its use for irrigation purpose are possible ways of heavy metals accumulation in plants food chain [1]; [2]. Several conventional methods are used for waste water treatment including coagulation-flocculation followed by sedimentation, filtration, precipitation, ion exchange resins and reverse osmosis before its distribution to consumers [3]; [4]. Many inorganic coagulants, synthetic inorganic polymer and naturally occurring coagulants are also widely used in conventional water treatment processes [4]. Nonetheless, use of ploy ammonium chloride, poly alumnium silico sulphate and inorganic alum salt is most common [5]; [6]; [7]. And use of aluminium containing coagulants is expensive and synthetic organic polymers have strong carcinogenic properties [8]; [9]. Further, aluminium is causative agent of neurological disorder presenile dementia and alum itself may induce Alzheimer’s disease [10] and have low coagulation efficiency when react with natural alkalinity in water leading to pH reduction [11]. Moringa oleifera Lam. is widely adapted in tropic and subtropics and cultivated in developing world. Its seeds are used as organic natural polymer containing polypeptide with cationic polyelectrolyte properties good for softening hard water by adsorption [ 12]. According to Ndabigengesere et al [ 13], aqueous extract of Moringa oleifera Lam. seeds contain stable and water soluble dimeric proteins active in coagulation. Many studies highlight the efficiency of Moringa oleifera seed extract as This study investigated the coagulation potential of Moringa oleifera seed powder (SP) or its seed aqueous extract (SAE) on pH, electrical conductivity (EC) and heavy metals of sewage water after 1, 3 and 6 h contact time. After optimizing, 2 g L−1 moringa SP, 40 mL L−1 SAE and 20 mg L−1 of alum alone or in combination were evaluated. Moringa SP was more effective than SAE and its combination to decrease EC and maintenance of pH of treated or untreated sewage water. Moringa SAE was more effective than SP or their combination to decrease Lead (Pb) and Chromium (Cr) load from sewage water. Naturally occurring amino acids in moringa seeds might increased the metal binding and decreased heavy metals load with maximum desorption on SP. Nonetheless, use of Moringa oleifera SP or its SAE can be inexpensive and alternative coagulant of sewage water treatment.