A UV disinfection system for waste water and drinking water, includes a number of UV radiators arranged in cladding tubes, the cladding tubes being configured essentially symmetrically to a longitudinal axis, as well as a cleaning device for the cladding tubes. The cleaning device includes at least one cleaning ring for each cladding tube, which surrounds the cladding tube, the at least one cleaning ring having a scraper ring resting against the cladding tube, at least one drive for driving the cleaning ring in the direction of the longitudinal axis, and supply provisions for supplying pressurized fluid under elevated pressure from a pressure source to the scraper ring are provided, wherein pressure may be applied onto the scraper ring from the pressure source in the direction of the cladding tube.