In 1839 Samuel Thornton received 100 acres at Irishtown, east of the present Saltash Street and south of Liverpool Road.

This scheme was to be Sydney's fourth water supply system, following the Tank Stream, Busby's Bore and the Botany (Lachlan) Swamps.

The second, Potts hill Reservoir 2, which has almost twice the capacity of the former, and was built in 1923 to supplement the first, and is also regarded as a component of the Upper Nepean scheme.

They currently operate as key service reservoirs for a large part of the south western metropolitan area.

1 is a rectangular shaped enclosure, constructed of earthen banks with puddled clay cores with a concrete floor.

This former railway siding, which was originally used to deliver coal to the steam-driven pumping station, now exists only as a remnant perway embankment across the site.

Attached to the southern side of the Boiler House is a former coal bunker, comprising opposing buttressed concrete walls, which is now used to store building materials.

It has a narrow verandah on its southern side beneath the roof overhang and sits on low brick piers.

East of this building is a smaller, single-roomed storage shed with corrugated iron cladding and a skillion roof.

The southernmost of these is a late Federation style, double fronted cottage of brick with a terracotta tiled roof.

Dating from c. 1960s, its roof has hipped gable ends and the projecting bay of the front facade features a curved corner of moulded bricks.

1 and separated by a drop in ground level of over 3m, is an area of abandoned industrial buildings which are all in poor condition and are cordoned off from entry.

These buildings have no direct association with the Reservoirs and, owing to a high level of industrial contamination, are due to be demolished in the near future.

The trees are important functionally because they act as windbreaks near the Reservoirs, minimising waves on the water surface which can put extra pressure on the built facilities.

Important features include the date palm tree boundary plantings along the Carrier Canal and surrounding much of Reservoir No.

[1] The Potts Hill Reservoirs are situated within a distinctive and attractive cultural landscape, combining functional industrial design, typical turn-of-the-century built features and both natural and exotic plantings.

The components of the site which are the most important in terms of the heritage values of the site are: The Carrier Canal and Associated items; Reservoir No.1 and associated items; The telescopic valve tower on the 1200mm Eastern Crossover; Pressure Tunnel Inlet; Pressure Tunnel Access Shaft Building; Suction Well; Surge Tank and Reflux Valve on No.1 Main; No.1 Supply Main Pipeline; No.2 Supply Main pipeline; the Pressure Tunnel; and Landscape Elements.

[1] Potts Hill Reservoirs 1 & 2 was listed on the New South Wales State Heritage Register on 18 November 1999 having satisfied the following criteria.

1, including its individual parts, demonstrates the attitudes towards water safety current at the time; -the layout of Reservoir No.

1, its surrounds and its security features display the early attitudes towards drinking water quality; -the former pumping station is an example of a functional industrial building of its period; and -Reservoir No.

1 contains the original intake to the Pressure Tunnel leading to Waterloo, which was and still is a major water supply line of Sydney.

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

Potts Hill Reservoir site is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement because: -Reservoir No.

1 and its parts demonstrate a past aesthetic style of public works; -through its materials and use of stylistic motifs in its structural features, Reservoir No.

1 is a handsome, well-proportioned structure with landscaped surrounds which together create a very scenic space; -The site is well proportioned with a clearly evident relationship between function, aesthetics and historical layers; -there are several pine and palm tree line plantations which show the importance of landscaping design to the early designers of the site; and -the carrier canal is a well-proportioned feature which relates to palm tree plantings spaced evenly on its sides creating a space of high scenic quality.

Potts Hill Reservoir Site has strong or special association with a particular community or cultural group in NSW for social, cultural or spiritual reasons because: - it is considered important by the National Trust of Australia (NSW), which is evidenced by its listing on the National Trust Register; and - is held in high esteem by many generations of Water Board workers.

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

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

[1] This Wikipedia article was originally based on Potts Hill Reservoirs 1 & 2 and Site, entry number 01333 in the New South Wales State Heritage Register published by the State of New South Wales (Department of Planning and Environment) 2018 under CC-BY 4.0 licence, accessed on 2 June 2018.