The history of wastewater in Wellington city

Back in 1865, with a population of around 7,460 in Wellington, the government began laying the first water mains from springs in Tinakori Road. Before this, people relied on wells, springs, streams, and rainfall to meet their water needs!

In 1872, the NZ Public Health Act banned cesspits and required cities to have sewerage systems. At the time, local leaders were opposed to the cost and decided that night soil collections and surface drainage were more effective and cheaper. 

However, Wellington’s growing population of 20,000 ended up having poor sanitation, with many dying from typhoid fever and cholera. 

Eighteen years later in 1890, and after 77 deaths that year attributed to bad drains, Wellington City Council appointed a Drainage Commission which recommended a sewerage scheme.

From this scheme, the Council was able to tackle the city’s sewerage woes. By 1899, after much tunnelling, Wellington had its first ‘wastewater system’ – a network of pipes in residential areas around the harbour and a large pipe called ‘the interceptor’, which collected the city’s flows from the gravity-fed pipe network to an outfall on the South Coast, near Moa Point.

As Wellington grew, smaller pipes were laid in the city and its growing suburbs – all linking to the interceptor. 

By the 1940s, advancements in technology and infrastructure allowed for the development of a more sophisticated water supply system with the construction of reservoirs, treatment plants, and distribution networks. 

Some key wastewater milestones include: 

• 1950s – the Kaiwharawhara tunnel and aqueduct, creating a major spine for the network from Ngauranga Gorge through the city to Moa Point.
• 1990s – Mount Albert wastewater tunnel built.
• 1998 – the Moa Point Wastewater Treatment Plant commissioned, along with the new ocean outfall, taking the now treated wastewater 1,800 metres offshore into Cook Strait.

Today, challenges remain. Our water pipes are old and in poor condition. That’s why the Council has been developing the 2024-34 Long-term Plan over the past two years, including working with the community to identify key outcomes and priorities for the city, such as water infrastructure resilience and wastewater. 

As we prepare for the future of wastewater management in Pōneke, construction is well underway on Te Whare Wai Para Nuku Moa Point sludge minimisation facility.

The facility will help us deliver on two critical targets the Council has set for reducing waste and carbon emissions in Wellington City. It will reduce carbon emissions created by treatment and processing by up to 60 percent, and it will reduce the volume of sludge produced by up to 80 percent.  

At the moment we bury dried sludge in the landfill. Our consents say that we must mix one part sludge with four parts waste, which limits how much we can reduce sending waste to landfill. 

The new facility will enable resilient, sustainable and climate friendly waste management which can meet the needs of our rapidly growing city.  

Alongside this, Wellington Water is also busy building a new rising main on Taranaki Street – a pipe that carries wastewater under pressure and allows wastewater to be diverted to the main interceptor, which will carry the wastewater to Moa Point.