A lamp assembly for use in a water treatment system. The lamp assembly includes a bulb assembly, a reflector assembly and a conduit carring liquid, such as water, through the lamp assembly. The reflector assembly is configured to reflect and focus light emitted from the bulb assembly on the conduit, thereby enhancing the efficiency of the lamp assembly. The reflector assembly can include reflectors including one or more diminishing radii of curvature, which terminate and form a peak near a bulb of the bulb assembly and/or conduit.