The crest and valve houses and inlet works retain original ironwork which represent a substantial repository of water supply delivery technology for the era. The place is important in demonstrating the principal characteristics of a class of cultural or natural places/environments in New South Wales. Woronora Dam is representative of a type of gravity dam constructed in New South Wales by the Water Supply and Sewerage Branch of the NSW Public Works Department and Water Board during the first half of the twentieth century. Key representative attributes of the Dam's design and construction include the use of cyclopean masonry bedded in sandstone concrete in the lower section of wall, use of blue metal concrete in the wall facings, use of a spillway set way from the gravity wall, valve and crest houses attractively designed and finished to a high standard, the use of an array of upstream intakes to regulate the quality of water supply, the internal inspection gallery, the foundation drainage system, the contraction joints, and the drainage system. The upgrading of the valves and ancillary monitoring and operating equipment is representative of modern-day safe operating practice. The construction technologies used at Woronora Dam are representative of dams constructed in New South Wales through the first half of the twentieth century. Key representative attributes include the use of cableways, the building of temporary camps to house labourers and tradesmen, building of semi-permanent cottages to house salaried staff, the construction of terraced platforms to for plant and machinery, mechanisation of concrete production, the construction of a purpose built road of access to transport men, supplies and materials from the nearest railhead to the construction site, the building of permanent infrastructure such as water supply for construction plant, men and horses, and the use of electricity to power plant and equipment. The rehabilitation of tracts of land scarred in the construction processes employed at Woronora Dam through beautification works is representative of practices undertaken at other dams throughout New South Wales. Key representative attributes of this practice include utilising the former terraced construction platforms as picnic areas and lookouts, and utilising the former construction roads and tramway for vehicular access to the dam site and dam wall. The practice of ongoing maintenance of the dam wall and pipeline after completion through surveillance provided by resident staff is representative of procedures undertaken at other dams and weirs constructed in New South Wales. The provision of public amenity at the Dam is representative of the use of large water supply and irrigation dams in New South Wales as places for recreation by the greater community.