The water demand of 500-10000 people can be provided from surface waters by the help of the CFS units. Surface water is treated continuously by the conventional treatment processes. The principle of the system is based on coagulation, flocculation and clarification processes. The water is primarily chlorinated for shock disinfection, and fed to the coagulation tank wherein coagulant is dosed. The coagulant binds small flocks together to make larger masses for faster settling. In the lamella type clarifier tank, the water is clarified and the treated water is fed by gravity to the storage tank. The stored water is chlorinated by an automatic dosage pump for final disinfection. According to the purpose of usage optional units can be appended to the system. For larger capacities the systems can be designed in parallel.