Peat water is a potential water source that can be used as clean water if being processed previously, humic acid removal becomes the main concern since it causes turbidity, high color intensity, and acidity in the peat water. One of methods that can be used to remove the humic acid from peat water is coagulation using chemical compounds in the form of a metal salt as coagulant. In this study, ferric chloride (FeCl3.6H2O) was used as the coagulant for humic acid removal. Determination of the optimum condition of coagulation was carried out with variation in pH (6-9) and FeCl3.6H2O doses (20-100 ppm). Coagulation was then conducted with the addition of chitosan as the coagulant-aid to improve the effectiveness of coagulation process,which chitosan dose was varied in the range of 10-40 ppm. It was obtained that the maximum pH value was 7 and FeCl3.6H2O dose was 80 ppm with a reductionin color and turbidity of 88.08% and 97.08%, respectively. Meanwhile, with the addition of chitosan up to 50 ppm, reduction in t-color and turbidity was increased to-94.75% and 99.07% respectively.