The objective of this research is to reduce fluoride concentration to a maximum target of 5.0 ppm (standard B). The scopes of this research include the effect of different coagulant dosages, coagulant types and pH effects. Poly-aluminium chloride (PAC) and mixture of sodium aluminate (SA) with sodium hydroxide (NaOH) were used as chemical coagulants. Samples of synthetic fluoride with concentration of 100 ppm were used in this research. It was found that increasing coagulant dosage enhances the de-fluoridation performance. 85.9 % of defluoridation efficiency was achieved using a 3.0 g/L of PAC with mixture of SA with NaOH at optimum pH of 7. Statistical analysis using ANOVA one-way test showed that the p value is 5.53×10-12 (p < 0.05), which concluded the chemical coagulant dosage provides significant effect on de-fluoridation performance.