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.