The Mosman Bay Sewage Aqueduct over Reid Park, completed in 1901 is one of two such structures in Sydney Water's portfolio of assets, which as a type are unique in New South Wales. The aqueduct was designed to provide the conveyance of sewerage over the bay as part of the Neutral Bay and Mosman branch sewerage scheme, one of the earliest of the lower north shore sewerage schemes constructed from 1891. The bridge was designed in the Sewerage Construction branch of the Department of Public Works in June 1899. The engineer-in-chief of this department was Joseph Davis. The design provided for an aqueduct to 'connect the second and third divisions of this sewer where it crosses the tidal waters at the head of Mosman Bay'. The design of a steel parabolic arch was evidently determined by need to provide a structure 'in such a way as to be no disfigurement to the locality (and) for convenience of foot passengers, a bridge will be built on top of the aqueduct'.
This structure is a magnificent piece of Federation era engineering purposely and attractively set within a public reserve. The structure is a key element in the historic built environment of the lower north shore, and continues to serve as a pedestrian right-of-way. The structure forms an intrinsic element of the landscaping of Reids Park and continues to be used.
The Mosman Bay Sewage Aqueduct was heritage listed on 1 January 2000.