Waiohine Water Treatment Plant
The Waiohine Water Treatment Plant was built in 2018.
It has a design capacity of treating up to 5.2 million litres a day, but it processes a daily average of 2.2 million litres.
The plant treats the water received from bores adjacent to the Waiohine River using UV disinfection, pH correction, and chlorination before being stored onsite and supplying Featherston and Greytown.
There is also a reservoir near the Waiohine plant that was brought into service in 2022. This provides additional water supply resilience for both towns.
If demand is higher than what the plant can supply, water from a bore located in Memorial Park is used to supplement Greytown’s supply.
The Waiohine plant currently provides around 38 percent of all the water supplied in South Wairarapa each year.
About the project
The Waiohine Water Treatment Plant pH dosing project will be underway from November 2025 and runs until May 2026.
The project involves replacing the current temporary caustic dosing system with a new permanent solution.
This work is being done to address operational health and safety issues and improve cost efficiencies.
The upgrade includes:
- A road and fence upgrade
- Bulk caustic storage for tanker delivery
- New pumps and controls for dosing
