Waikato River

The Waikato River supplies up to 75,000 cubic metres of water to Auckland every day, meeting around 10% of the region's needs.

The Waikato Water Treatment Plant is the most sophisticated plant in Australasia and uses membrane filter technology. The water passes through a four-stage, ultra-filtration treatment process using membrane filters to eliminate microbiological, chemical and radiological contaminants either completely or to the point where any residual amounts will be safe. The pores of the membrane filters are so small (about 15 times smaller than the filter system in household water filters) that they prevent the spores of parasites, giardia and cryptosporidium, from getting through.

Environmental impact on the river is minimal because the water is abstracted just before it goes into the Tasman Sea. When there are low river levels, less than one percent of the river's volume will be needed. It is a drought resistant, cost-effective source of supply that is not dependent upon rainfall like the dams.