Getting to a treatment plant

Our wastewater network transports the wastewater from your house to the treatment plant (it can be imagined as a city transport network).

  1. The network begins at the laterals of your property. They are the ‘driveways’ in the network.

  2. These laterals then connect to small pipes called service branch lines - these pipes are the ‘suburbs’ (the groves, crescents, streets etc.) in the network. They are usually 150mm in diameter.

  3. Service branch lines then link to reticulation mains, which are larger pipes and can carry more wastewater - these are similar to the ‘main roads’ around your city. They are usually 225-375mm in diameter.

  4. Finally, there are the trunk sewers, which carry the wastewater all the way to the treatment plant - this is similar to a state highway leading out of a city. They are usually larger than 400mm and can be as big as 1,800 mm in diameter (big enough to walk through!)

At certain points along the network there are maintenance chambers/man-holes. Network operators use these as access points to make quick repairs.

There are also pump stations at points in the network where wastewater needs to be pumped up a hill, or into the trunk sewer.


The wastewater network leads to the one of Wellington's four treatment plants.

True or Poo network