Low concentrations of contaminants in rainwater is the primary benefit of transforming it as an alternative source of drinking water. However, treatment is necessary as rainwater collects contaminants that are persistent in the environment such as lindane and E.coli. The combination of photocatalysis and adsorption processes was chosen as the treatment method in this study. From the results obtained, photocatalysis treatment process was able to degrade lindane in synthetic rainwater under different experimental conditions such as pH, titanium dioxide (TiO2) dosage, and initial concentration. The photodegradation process of lindane followed pseudo kinetic first order. In adsorption process, the adsorbents used in the process are limestone and laterite soil. The performance of these adsorbents are determined by carrying out an equilibrium batch study.The experimental works show that limestone and laterite soil able to remove E. coli at 99%. The optimum dosage of limestone and laterite soil to remove E. coli from synthetic rainwater is 6g and 2g, respectively. The results were then analysed by developing Langmuir and Freundlich isotherm model. Overall, the processes of photocatalysis and adsorption showed a good performance in removing lindane and E.coli from the synthetic rainwater respectively.