Prospect Reservoir Valve House, Heritage-listed valve house in Prospect, Blacktown, Australia

The Prospect Reservoir Valve House is a heritage-listed waterworks building in Prospect, New South Wales, designed and built by The Metropolitan Board of Water Supply and Sewerage. It stands on the grounds of Prospect Nature Reserve and is owned by Sydney Water and Water NSW. The building controls water flow from Prospect Reservoir into the Lower Canal.

The valve house was designed and built by The Metropolitan Board of Water Supply and Sewerage on the grounds of what is now Prospect Nature Reserve. It is owned by Sydney Water and Water NSW, agencies of the New South Wales Government, and was added to the New South Wales State Heritage Register on 18 November 1999. The surrounding Prospect area was settled by Europeans by 1789, and Governor Phillip's party climbed nearby Prospect Hill on 26 April 1788.

Archaeological surveys here found glass flakes mixed with stone flakes, showing Aboriginal occupation continued after European contact. A meeting on 3 May 1805 near Prospect Hill, arranged by Reverend Marsden at the suggestion of local Aboriginal groups, ended the frontier conflict around Parramatta and Prospect; Aboriginal women and a young settler, John Kennedy, acted as intermediaries.

The valve house stands on the grounds of Prospect Nature Reserve, east of the reservoir, in the City of Blacktown local government area; the structured data placing it in Fairfield City Council is wrong. It is owned by Sydney Water and Water NSW. The sources give no opening hours, admission fees or trail conditions, so check access with the managing agencies before travelling.

The valve house stands on land where Aboriginal groups met Reverend Marsden on 3 May 1805, a conference that ended frontier conflict around Parramatta and Prospect; Aboriginal women and a young settler, John Kennedy, acted as intermediaries. The Sydney Gazette report of the meeting notably lacked the sneering tone of its earlier coverage.