In the past, spectroscopic applications with fiber optics have been restricted to the wavelength range above 230 nm, because standard silica fibers with an undoped core and fluorine doped cladding are frequently damaged by exposure to UV-light, especially below 230 nm so quickly that stable UV-light transmission is impossible. Work on a fiber-optic sensor for water monitoring is presented here using an absorption cell and first solarization-reduced fiber samples for light-transportation: the main UV-band around 210 nm shows an induced loss of less than 0.3 dB/m. In this case it was possible to have the full output spectrum of a deuterium lamp at fiber endface, stable over time. Therefore, an optimized UV-lamp-fiber system, including commercially available components, has been developed and is reviewed in terms of performance in the wavelength region around 200 nm, in respect of an effective sensor approach for water a monitoring. In the following step, modification of the deuterium-lamp optics for optimized light coupling becomes more important, in order to maximize the optical power budget for this wavelength-region.