In the early 1900s, a connected system for stormwater and sewage was established in the CBD and inner suburbs of Auckland, known as the Auckland Isthmus. The system discharged untreated sewage and stormwater straight into Waitematā Harbour. This continued until the completion of the Māngere Treatment Plant in 1960.
The system we have was designed to meet the needs of the early to mid-1900s. These combined networks now struggle to handle the current volume of both sewage and stormwater. This leads to overflow into waterways, particularly during heavy rainfall. Waitematā Harbour then becomes polluted, posing risks to swimming and other recreational activities.