Increasing interest in sustainable Greywater treatment has driven the exploration of Plant-based coagulants as substitutes for traditional chemical coagulants. This study evaluates the coagulation efficiency of sweet sop (custard apple) (Annona squamosa) leaf extract prepared using three extraction media: NaCl (0.25, 0.5, 1 M), NaOH (0.025, 0.05, 0.1 M), and HCl (0.025, 0.05, 0.1 M). Custard apple leaves were collected, washed, shade-dried, powdered (<0.35 mm), and characterized using Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared Spectroscopy (FTIR) to identify functional groups and surface morphological features relevant to coagulation. Freshly prepared liquid extracts from each molarity were applied in jar tests at dosages of 0–50 ml using collected Greywater. Pre- and post-treatment analyses included pH, turbidity, hardness, acidity, alkalinity, TDS, TSS, chloride, and residual chlorine. A parallel jar test series using alum (10–50 ml) was conducted to benchmark performance. The NaOH extract exhibited the highest turbidity and TSS removal efficiencies, whereas NaCl and HCl extracts showed comparatively moderate performance. Optimum dosage varied with the extraction medium, with performance improvements observed up to 30–40 ml.At 50 ml dosage, alum reduced turbidity to 9.8 NTU and TSS to 48 mg/l but lowered the pH from 7.6 to 4.38. The 0.1 M NaOH extract achieved similar turbidity reduction (10.2 NTU) with pH maintained between 7.6 and 8.24. One-way ANOVA (SPSS 20) confirmed significant effects of extraction medium, molarity, and dosage on treatment performance (p < 0.05). The results demonstrate that custard apple leaf extract is a promising, low-cost and eco-friendly coagulant appropriate for applications involving decentralized greywater treatment.