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Your wastewater services

Providing clean drinking water to your home, school, or business is only half of Watercare’s role. Once water has been used, wastewater is collected, treated, and returned safely to the environment. Each day, Watercare collects and treats approximately 400 million litres of wastewater. 

What is wastewater?

Each time you flush the toilet, pull the plug from a sink, or have a shower, the wastewater drains into a sewer pipe on your property. Wastewater, also known as ‘sewage’, is 99.97 percent water as the majority comes from showers, baths, and washing machines. The remainder includes organic matter such as human waste and food scraps, fats, oil and grease, and debris such as sand, grit, and plastic. Wastewater can also include such things as household chemicals, paint, and pharmaceuticals that can be harmful to our health and to our harbours and waterways, so effective treatment is very important. 

Where does Auckland’s wastewater go?

Your wastewater is transported through an 8000 kilometre public wastewater network to one of 18 wastewater treatment plants. However, the majority of Auckland’s wastewater is treated at either the Mangere or Rosedale treatment plants. 

Here the wastewater is treated to produce treated wastewater and biosolids to standards that protect public health, the local environment and our coasts and harbours. Watercare is continually seeking more environmentally friendly ways of doing this.




 - The history of wastewater treatment in Auckland 

Wastewater Treatment

 - Process overview

 - Primary treatment 

 - Secondary treatment - liquid

 - Secondary treatment - solid waste

 - Tertiary treatment

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