The Gadigal (or Cadigal) people were the Aboriginal group most commonly accepted to have lived around the Sydney Cove area prior to European arrival.

The area was chosen by the commander of the First Fleet, Captain Arthur Phillip, R.N., in 1788 as the location for the New South Wales colony for similar reasons.

[1] The Tank Stream rose in marshy ground roughly bounded by what is now Elizabeth, Market, Pitt and Park Streets.

Prior to 1888 Tank Stream also carried salt water, stored in council reservoirs for the purpose of street cleaning and dust suppression.

[6]: 2  The Tank Stream could not meet the needs of the growing colony and, despite efforts by successive Governors, it became increasingly polluted by runoff from the settlement.

This has destroyed a number of sections of the channel and is largely tied to post-World War II redevelopment where little regard was paid to the historic value of the Tank Stream.

The Australia Square Tower basement houses the access to Tank Stream for public tours and as an inspection point for Sydney Water.

[1] The surviving fabric documents mid-nineteenth century sanitation design and construction, and subsequent changes in methods and also the theory of urban wastewater management.

[1] The sections of the former Tank Stream south of King Street which survive have potential for retaining evidence of the earliest periods of its human use, although this is likely to have been severely compromised by development.

The original watercourse and catchment would have provided a resource for exploitation by the Gadigal people who occupied the southern shore of Sydney Harbour at contact and their ancestors.

As a result of the severity of this displacement the Tank Stream has become symbolic of the European settlers immediate appropriation of essential resources and Aboriginal dispossession.

The course of the stream determined Phillip's siting of the first camp and this early administrative decision influenced the subsequent urban form of Sydney.

[19][1] The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales.

The Tank Stream features fine quality stonemasonry and brickwork from the nineteenth century, houman scale and an intriguing form showing layers of different phases of construction.

The Tank Stream is of State significance for its recognition in the community with the placement of Sydney in its current location, as evidenced by the popularity of tours.

[1] The place has potential to yield information that will contribute to an understanding of the cultural or natural history of New South Wales.

The sections of the former Tank Stream south of King Street which survive have potential for retaining evidence of the earliest periods of its human use.

The swampy source of the stream may provide evidence of past environmental conditions and potentially of Aboriginal occupation prior to European arrival.

[1] The place possesses uncommon, rare or endangered aspects of the cultural or natural history of New South Wales.

[1] The fabric of the Tanks Tream and its enclosing stormwater drain contains rare surviving evidence of the eighteenth and nineteenth century water supply and sewerage construction in the one linear site.

The Tank Stream is representative of a significant collection of water and wastewater heritage assets from the mid-nineteenth century onwards.

[1] The fabric of the Tank Stream and of the enclosing stormwater drain is representative of a range of technologies associated with water reticulation, sewerage and drainage for a period of two centuries.