Vanadislundens vattenreservoar, Water tower in Vasastaden, Stockholm, Sweden.

Vanadislundens vattenreservoar is a water tank in Vasastaden, Stockholm, featuring four corner towers and red Helsingborg brick walls built on a solid granite foundation. The structure sits at the highest point of Vanadislunden park with a roof finished in glazed tiles.

The first reservoir on this site, a nearly square structure with grey stone walls and a brick roof covered in topsoil and grass, entered service in 1879 holding 5,000 m³. Its top water level of 47 metres proved too low for the mains fed from Norsborg and Trekantsreservoaren, so a replacement by architect Gustaf Améen was built in 1913–1918 on the same foundation, holding 8,100 m³ at 54 metres.

The reservoir's outer granite walls are the surviving walls of the 1879 basin, which the 1913–1918 brick structure was built around and above. The four corner towers and the red Helsingborg brick give the water facility the look of a castle, a form Stockholm repeated in other reservoirs of the period.

The water tank is located at the highest point of Vanadislunden park and is easily accessible on foot. Visitors can view the structure from the outside and explore the park grounds surrounding the building.

In 1954, a broken cast iron valve caused eight million liters of water to leak, leading to emergency evacuations in neighboring areas. This incident revealed how critical the tank was to the city's water supply.