Ohakune Water Supply

​The Ohakune Water Supply System provides potable water to approximately 1,880 properties within the Ohakune community.

Where does my water come from?

Water for the Ohakune Water Supply is taken from the Tutara (Serpentine) Stream, a tributary of the Mangawhero River, located within the Tongariro National Park.

Is my water treated?

Yes. Water is gravity piped to the Ohakune Water Treatment Plant where it undergoes the following processes:

  1. Sediment Settling
    Small unwanted particles or solids, such as fine sand and dirt, are removed from the water by adding a coagulant which gathers the solids into a cluster, creating larger solids which quickly settle to the bottom. Clean water can be taken from the top.  This process takes place within the pipework.

  2. Finer Filtration
    Water is passed through layers of sand and gravel to further remove impurities. Small water molecules pass through the holes between sand and gravel pieces and clean water is collected in a drain at the bottom. Unwanted solids get stuck in the holes, and are thus retained in the sand and gravel medium. This medium is washed from time to time to remove the unwanted solids.

  3. Ultra Violet (UV) irradiation
    Water is further treated by exposure to Ultra Violet light. This kills any bacteria and viruses remaining in the water supply by destroying their genetic core (DNA). It is also effective against many protozoa.

  4. Chlorination
    The water is dosed with  low levels of chlorine to kill off contaminants (bugs) in the reservoirs and pipes.

Water monitoring

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

Where is my water stored?

Treated water is stored within two reservoirs (1500m3 each) and gravity supplied to consumers within the township.  


Our pipelines

The Ohakune Water Supply Reticulation Network consists of around 38km of pipeline.  The reticulation network is tested for Free Available Chlorine throughout the township on a regular basis.

The following schematic shows flow through the Ohakune Water Supply system.



Page reviewed: 25 Feb 2016 2:41pm