Planning ahead

Over coming decades, we want to keep reducing the volume and number of overflows from the wastewater network.

Overflows happen when rainwater overwhelms the wastewater pipe network, causing untreated wastewater to flow over land or into freshwater. This is objectionable, and abhorrent to mana whenua. Overflows contain bacteria that may make people sick if they come into contact with contaminated water.

We know where and when overflows happen from our monitoring, incidents reported by the community, and network modelling. Wellington Water and Porirua City Council have a view of where work is needed to reduce overflows and have already started on improvements.   For example, the central wastewater storage tank will reduce overflows into Porirua Stream, and the Eastern Porirua regeneration project will reduce overflows into Kenepuru Stream.

You can find out more about the current network improvement programme in this report or by looking at this presentation from a public meeting in June 2021.

The next step is to formalise a process, through a resource consent, for:

  • Reducing the volume and number of overflows from the wastewater network
  • Setting network standards – that is, the volume of overflows we should aim for, taking into account costs and benefits
  • Recommending priorities for improvement.

We’re proposing this happens through a collaborative process involving Ngāti Toa with the council and Wellington Water.

If you have any questions, please email us at