The article deals with the creation and development of the water system of the capital city of Kraków throughout centuries. The channel supplying water to fortifications systems, moving mills, (the name of Młynówka derives from it), fullers, serving tanneries, bleacheries, forges, grinderies and other workshops, supplying water to baths, gardens, fish ponds, etc. was significant to the city. The other text is an overview of the current situation of the Młynówka Królewska. A part of it runs across highly urbanized areas via a vaulted bed, and its upstream section flows along a charming tourist route.