Delivering light into reactors to enable nanomaterials, and separating nanomaterials from water, are two barriers to broadening the use of nanomaterials for drinking water. Optical fibers provide new modalities to deliver UV-A, B, C or visible light into a wide variety of reactor geometries. This presentation will cover three novel water treatment objectives that can be achieved using optical fibers coated with nanomaterials, including destruction of organics, removal of hardness, and disinfection. The physics of light and interactions within optical fibers will be discussed, with the intent of maximizing effectiveness of light enabling nano-technology related reactions. Attaching nanomaterials, securely, to optical fibers prevents concern about their release into drinking water – and in some cases limits their ability to be fouled by non-targeted constituents in water.