Wahroonga Reservoir, Heritage-listed elevated water reservoir in Wahroonga, New South Wales, Australia

Wahroonga Reservoir is a cylindrical riveted steel tank with a rounded base and original roof, mounted on an eight-legged H-section steel frame with horizontal and diagonal bracing. An internal stairway climbs the frame to a walkway and then to the roof. Its full service level is 237 metres and its capacity is 1.1 megalitres.

The Metropolitan Board of Water Supply and Sewerage built this tank in 1915 to meet growing water needs in Sydney's northern suburbs. This project was a key step in expanding the water network across the region during a period of rapid residential growth.

The tank's name, Wahroonga Reservoir (Elevated) WS 0124, comes from the Sydney Water asset numbering system. The site is a local landmark on the Pacific Highway, and the adjacent riveted steel storage tank and the high brick-walled "Woonona Avenue" building opposite, probably the 1935 pumping station, are part of the same waterworks group.

The site is visible and accessible from the nearby sidewalk during daytime, though it sits at a busy street corner. Visitors get the best view from across the street where they can see the full structure without stepping into traffic.

The tank's full service level is 237 metres above sea level, and it holds 1.1 megalitres. A stairway climbs the inside of the eight-legged frame to a walkway at the top, then continues to the roof. A davit and a trigonometric station are among the standard fittings on the structure.