Water storage

Water storage is simply capturing and storing water for later use. WaterNSW stores water in dams and weirs along river systems or in reservoirs.

Our storages are so large that we measure the amount of water in them using megalitres (ML) and gigalitres (GL).

But how big is a megalitre or gigalitre? A megalitre is one million litres of water (1,000,000 litres), while a gigalitre is one billion litres of water (1,000,000,000).

In Greater Sydney, WaterNSW collects water from river catchments to the south and west of Sydney, storing it in 11 major dams, and transporting it between storages via a network of rivers, pipes and canals. The Greater Sydney system is complex yet highly flexible, allowing us to draw water from different storages for supply to Sydney Water's water filtration plants and some local councils.

Warragamba Dam is Greater Sydney's major supply dam, with a storage capacity of 2,064,680 ML. It stores water, ready for transfer to Prospect Water Filtration Plant, operated by Sydney Water, which supplies approximately 80% of Sydney's drinking water.

In regional NSW, WaterNSW captures and stores water in weirs and dams, including 18 large dams. These dams are located across the state on 12 major river systems, including Border Rivers, Gwydir, Namoi and Peel to the north; Lower-Darling, Murray and Murrumbidgee to the south; Bega/Brogo, Hunter/Paterson and Richmond on the Coast; and Lachlan and Macquarie Rivers in Central NSW.