Where does Auckland’s water come from?
Auckland’s water supply is obtained from three different sources: dams, rivers and underground aquifers. The exact proportion of water supply from each source varies daily depending on the levels in the storage lakes, forecast rainfall, treatment plant capacity, maintenance requirements and transmission costs.
Auckland’s dams are located mainly in the Hunua and Waitakere ranges; together they supply around 80 per cent of the region’s drinking water. The combined reservoir capacity of Auckland’s storage lakes is over 100 billion litres.
Auckland’s river water is sourced from three rivers: the Waikato River, Mahurangi River, and the Hoteo River. The Waikato River provided around eight percent of metropolitan Auckland’s drinking water needs in 2010/2011. The Mahurangi and Hoteo rivers supply Warkworth and Wellsford respectively.
Auckland’s groundwater supply comes from rain which percolates down through the soil or rock fractures, filling up the pores between sand grains or the fissures in rock. A small percentage of Auckland’s drinking water is sourced from groundwater supplies. There are a number of groundwater sources servicing the drinking water needs of local Auckland communities. These are located at Onehunga, Muriwai, Hamiltons Road (Algies Bay/Snells Beach), Waiuku, and Bombay.