The natural variability of catchment waters in karst areas requires treatment in order to respect the turbidity limit in the water supply. This water treatment reduces the range to be expected from protection areas. The creation of immediate, main and satellite protection areas is necessary. The longitudinal extension proposed for the inner protection area is based on a water transit time of 2 hours for the highest speeds in the aquifer under consideration. Delineating the inner protection area in such a way serves as a buffer in the event of accidental pollution. The selected intervention timeline allows for the interruption of pumping and keeps extraction and treatment equipment safe. The implementation of an outer protection area corresponding to a caution area may supplement the protection.