Participate Palmy

Option 6: Most of the treated wastewater discharged to the ocean, and some applied to land

Most of the treated wastewater would be discharged into the ocean from an outfall pipe likely to extend at least 2km out to sea. A small portion would be discharged to land during the drier months of the year, and the existing discharge point to the Manawatū River would be used on an exceptional basis, when flows are at their highest (approximately 3% of the time).

Photo shows illustration of treated wastewater discharged to the ocean, and some applied to land.

We’d be looking at a discharge in the South Taranaki Bight, which is off the Horowhenua/Manawatū coast.

The ocean is a common environment for discharging wastewater in New Zealand. This option may offer the best opportunity to accommodate a combined scheme with other councils or large businesses.

If this option is preferred by the public we will conduct thorough investigations to clearly understand the recreational impact.

What we'd need to install or build

As we are at least 30km from the coast, this option would require significant investment in pipes, pump stations and storage to move treated wastewater to the coast.

In addition, this option would require leasing or purchasing approximately 680 to 850 hectares of land and installing irrigation infrastructure.


  • Lifetime cost: $610-753 million
  • Potential rate increase per year: $740-900
  • Total wastewater charge per rateable unit per year: $1,000-1,200