A fluid heating system may include a solar collection system configured for focusing sunlight on a focal axis, an elongated flow element arranged and configured for transporting fluid along the solar collection system at the focal axis, and a flow-control assembly comprising thermostatic valves configured to control the flow of the fluid in the elongated flow element such that pathogens present in the fluid are substantially inactivated before the fluid exits the fluid heating system. A method of operating a fluid heating system wherein the fluid heating system comprises a parabolic solar collector and a support structure may also be provided.