History: 1973 onwards

From Regional Water Board to Regional Council

1973 - the Wellington Regional Water Board (WRWB) was formed, in response to an act of parliament requiring water resources to be managed on a regional basis. The Hutt River Board and the Hutt Valley Underground Water Authority became part of the Regional Water Board. For the first time, the water supply resources of the Wellington region were consolidated under a single controlling authority.

1980 - the Wellington Regional Council (WRC) was formed, incorporating the Regional Water Board and the Regional Planning Authority. The Wellington Regional Council assumed responsibility for collection and treatment of water for greater Wellington.

1981 - Waterloo Treatment Plant was built to supply artesian bore-water to Lower Hutt, Eastbourne and Wellington. Waterloo replaced the Hutt Park Pumping Station in supplying Lower Hutt and Eastbourne.

1987 - a treatment plant, pumping station and storage lakes were completed at Te Marua. The new plant introduced a four-stage treatment process - coagulation, flocculation, filtration and disinfection - marking a major advance in water treatment, while the storage lakes improved security against shortages or water quality problems in the supply rivers by providing a back-up source of water for treatment.

1989 - the Morton Dam was decommissioned due to concerns about its ability to withstand a major earthquake. Weirs and water intakes were built on the Wainuiomata River and George Creek as a direct replacement for the dam.

1992 - the UpperKarori Reservoir was decommissioned, also following earthquake safety concerns. Ngauranga Pumping Station was built to further improve water supply security to the four cities of the region. It linked the two main supply pipelines, Te Marua - Wellington and Wainuiomata - Wellington, and allowed for water to be pumped from one to the other so that each city has more than one source of water supply.

1993 - Wainuiomata Treatment Plant was built to fully treat water from the Wainuiomata and Orongorongo water collection areas. The Wainuiomata plant uses a similar four-stage treatment process to that adopted at Te Marua six years earlier.

1997 - The Lower Karori Reservoir ceased to be used for water supply following the construction of a new closed reservoir at Ngauranga. Open storage was no longer considered sufficiently secure from the threat of waterborne disease.

Since 1997 - Wellington Regional Council (now Greater Wellington Regional Council) has concentrated on improving the efficiency of production from its Te Marua, Wainuiomata and Waterloo water treatment plants, thus reducing the cost and environmental impact of supplying water. Buick Street Pumping Station was closed in 1999, and Petone now receives its water supply from the Waterloo Treatment Plant.