Raetihi Water Supply

Raw water monitoring

Water taken for supply is monitored for hydrocarbons before reaching the settling ponds. The hydrocarbon sensor (shown below) will send a signal to switch off the water take from the Makotuku River if hydrocarbons are detected.

Is my water treated?

The upgrade of the Raetihi Water Treatment Plant has seen the water treatment process increase from six stages up to thirteen stages with the addition of carbon dosing, flocculation tanks, filtration, UV disinfection and chlorine disinfection. Here is a diagram of the new schematic for the Raetihi Water Treatment Plant (RWTP) alongside the schematic design before the upgrade.

From the abstraction point at Tohunga Junction (State Highway 49 Bridge), gravity pressure is used to pipe the 'raw' water (or untreated water) to the settling ponds and eventually up to the Raetihi Water Treatment Plant located 7.4km away.

Where is my water stored?

Treated water is stored in the Raetihi water reservoir which provides storage for 900m3 (900,000L) of treated water. The upgrade included site development, flocculation tanks and a fit-for-purpose building shown in the photo below.

Water monitoring and treatment

Online monitoring through Supervisory Control and Data Acquisition (SCADA) provides information about the water treatment. This system checks that water parameters stay within set values for 24 hours every day and will alert the Plant Operator if it changes.

For example the amount of Chlorine added is managed through an automated monitoring and dosing system (shown below). The Raetihi Water Treatment Plant operates two independent chlorine analysers to ensure a safe chlorine dose entering and leaving the reservoir. Levels of Chlorine added to water supplies are regulated through Government legislation and must fall within guidelines set by Drinking Water Standards New Zealand.

Our pipelines

The Raetihi Water Supply reticulation network consists of around 24km of pipeline. The entire network is gravity supplied. Most pipes are between 100 and 200mm in diameter with the more common material being Asbestos Cement. Sections of the township are being upgraded each year to new PVC pipework.

The following image highlights (in red) where water service pipes in Raetihi township have been upgraded or replaced with brand new pipes from 1998 to 2018.

Community Open Day - Raetihi Water Treatment Plant

On 5 August 2018, Ruapehu District Council and Veolia hosted a Community Open day in Raetihi for the Raetihi community. The event was supported by Ruapehu District's Mayor Don Cameron, RDC's Chief Executive Clive Manley and in attendance were Iwi representatives from Ngati Uenuku, long time Raetihi residents, RDC and Veolia staff. The purpose of the day was to provide the opportunity for residents of Raetihi, local councilors and stakeholders to be guided around the plant and to see the new technology installed for the treatment of Raetihi town water supply.