Constructed to provide the city with fresh water in times of need, these massive reservoirs purify rainwater by acting as settling tanks and filtering down sediments. The system is composed of several connected sections, from a smaller basin, to a larger one, to a decorated masonry water tank.

Source: game/common/buildings/ccp3_special_buildings.txt, game/common/holdings/00_holdings.txt, game/common/script_values/00_building_values.txt and the English localisation, Crusader Kings III 1.20.0.3.