Watercare Services Limited, North Island, New Zealand – Exploring purified recycled water after Citizens Assembly recommendation
Watercare currently operates 28 sources comprising dams, rivers, and aquifers. 15 sources provide water to Auckland’s metropolitan area, which has a population of around 1.4 million. About 98% of the water Watercare treats supplies this area, which is operated as an integrated network. Watercare also provides water services to eight rural communities, each with its own stand-alone supply.
Watercare is investigating purified recycled water as a future water source option and is not currently supplying it to customers. We do, however, have unacknowledged reuse with our largest river source where there are several communities and wastewater discharge locations upstream of the abstraction point.
Purified recycled water is being investigated as an option for the next major drinking water source beyond 2040. If Watercare were to pursue purified recycled water, a scheme is expected to become operational mid-2040s.
The primary drivers for pursuing purified recycled water as a future water source option are population growth, resilience to drought/climate change and the cost-effectiveness of this option. There are also limited opportunities to take additional surface and groundwater from within the Auckland region. We anticipate that we will need at least an additional supply capacity of 150 million litres (39 million gallons) a day by mid-2040s. Diversifying our water supply portfolio using rainfall-independent sources will help us achieve a more resilient and reliable water supply.
Watercare has built a small-scale purified recycled water pilot plant at its Māngere Wastewater Treatment Plant facility. Tertiary treated wastewater provides source water to the pilot plant. Treatment processes utilised are UF, RO, UV-AOP, GAC, and chlorination. The pilot plant was commissioned in early 2024. Data gathered during piloting will be used to evaluate the feasibility of purified recycled water as a future water source option, guide full-scale facility planning and design, support permitting, and support drinking water regulatory development. Additionally, the facility will provide a venue for conducting tours and educating stakeholders on water purification processes, helping to build operational capability and social license for purified recycled water.
Engaging with our community
Between August and September 2022, Watercare collaborated with the University of Auckland to host a Citizens’ Assembly based on the question: “What should be the next source of water for Auckland beyond 2040?”. Independent experts provided information to the 37 assembly members – representative of Auckland based on age, gender, ethnicity, education, and home ownership – so they could understand the complexity of this issue and the different water source options.
At the end of the two-month process, the citizens prepared a report outlining their final recommendations. The group recommended that direct purified recycled water be pursued as the next major water source for Auckland and that Watercare continue to educate the public on the safety and quality of this option.
Watercare will collaborate and consult with Māori (Indigenous population of New Zealand), communities, and other stakeholders before making decisions on long-term water and wastewater solutions. We will also partner with Māori to co-design solutions that address any cultural sensitivities.
Related resources
Citizens’ Assembly recommends direct recycled water for Auckland’s future water source
New Zealand’s first wastewater recycling plant launched in Mangere
Citizens Assembly video