The Potts Hill Water Supply Reservoirs were an integral part of the Upper Nepean Water Supply Scheme, which was crucial to the development and growth of Sydney from the late nineteenth century.
The expansion of the complex, including the construction of Reservoir No.
2, demonstrates the growth of the City of Sydney and surrounding suburbs for more than a century.
The construction of the Reservoirs was a major achievement in hydraulic technology and associated construction methods for the time and today, the site continues to feature substantial physical evidence of these achievements, including extensive areas of subsurface water reticulation.
The complex includes the inlet for an early twentieth-century high pressure tunnel, which was an outstanding engineering feat and was the third largest water supply tunnel in the world for its time.
The Reservoirs continue in an important functional role as a distribution centre for Sydney's water supply.

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 two reservoirs in combination are rare because of their size, method of construction and proximity.
The Potts Hill Reservoirs are an important element in the history of Sydney Water and the site continues to be held in affection and esteem by many generations of Water Board workers.
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.

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

The place is important in demonstrating the course, or pattern, of cultural or natural history in New South Wales.

Potts Hill Reservoir site is important in the course, or pattern, of NSW's cultural or natural history because: -Reservoir No.
1 was the main component of the original Potts Hill site; -Reservoir No.
1 is a relic of an earlier technological period of Sydney water resource management; -it has essential links with the function and development of Sydney for over 100 years; -the site displays changes in usage through different periods of Sydney water resources management; -Reservoir No.
1 was a major engineering project of its time and a major public work; -it is an important component of the Upper Nepean Water Supply Scheme, one of the largest public works undertaken in Australia; -the walls of Reservoir No.
1 are lined using sandstone block construction, a method which is no longer practised in Australia; -the site still contains remnants of its former pumping station, an element which was essential to the early function of the site; -the position of the Reservoir No.
1 on the highest point in the region displays its original function as a gravity-fed water system; -the site still contains the original pipe head of the Pressure Tunnel, once the most important water pipeline in Sydney; -the site contains many penstocks displaying a range of valve designs which have now been superseded; -it contains an early employee residence which shows the standard of accommodation for water management staff in the early years of the site; -the changing economics and attitudes of the Water Board are represented in the different building styles and standards around the site; -the design of Reservoir No.
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 indus
The Potts Hill Water Supply Reservoirs were an integral part of the Upper Nepean Water Supply Scheme, which was crucial to the development and growth of Sydney from the late nineteenth century. The expansion of the complex, including the construction of Reservoir No. 2, demonstrates the growth of the City of Sydney and surrounding suburbs for more than a century. The construction of the Reservoirs was a major achievement in hydraulic technology and associated construction methods for the time and today, the site continues to feature substantial physical evidence of these achievements, including extensive areas of subsurface water reticulation. The complex includes the inlet for an early twentieth-century high pressure tunnel, which was an outstanding engineering feat and was the third largest water supply tunnel in the world for its time. The Reservoirs continue in an important functional role as a distribution centre for Sydney's water supply.
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 two reservoirs in combination are rare because of their size, method of construction and proximity. The Potts Hill Reservoirs are an important element in the history of Sydney Water and the site continues to be held in affection and esteem by many generations of Water Board workers. 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.
Potts Hill Reservoirs 1 & 2 was listed on the New South Wales State Heritage Register on 18 November 1999 having satisfied the following criteria.
The place is important in demonstrating the course, or pattern, of cultural or natural history in New South Wales.
Potts Hill Reservoir site is important in the course, or pattern, of NSW's cultural or natural history because: -Reservoir No. 1 was the main component of the original Potts Hill site; -Reservoir No. 1 is a relic of an earlier technological period of Sydney water resource management; -it has essential links with the function and development of Sydney for over 100 years; -the site displays changes in usage through different periods of Sydney water resources management; -Reservoir No. 1 was a major engineering project of its time and a major public work; -it is an important component of the Upper Nepean Water Supply Scheme, one of the largest public works undertaken in Australia; -the walls of Reservoir No. 1 are lined using sandstone block construction, a method which is no longer practised in Australia; -the site still contains remnants of its former pumping station, an element which was essential to the early function of the site; -the position of the Reservoir No. 1 on the highest point in the region displays its original function as a gravity-fed water system; -the site still contains the original pipe head of the Pressure Tunnel, once the most important water pipeline in Sydney; -the site contains many penstocks displaying a range of valve designs which have now been superseded; -it contains an early employee residence which shows the standard of accommodation for water management staff in the early years of the site; -the changing economics and attitudes of the Water Board are represented in the different building styles and standards around the site; -the design of Reservoir No. 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 indus
Potts Hill Reservoirs 1 and 2