Te Pūnaha Maimoatanga Wai o Ōākura

Okato Water Treatment Plant

Source of water

Mangatete Stream

Present capacity



  • Bank infiltration gallery
  • Cartridge filtration
  • Ultraviolet disinfection
  • Disinfection (chlorination)
  • pH adjustment (lime)

The water treatment process

Water from the Mangatete Stream is drawn through an infiltration gallery under the riverbank and flows by gravity to the treatment plant where the following multi-barrier process occurs:

Two-stage microfiltration – two banks of cartridge filters operate in parallel to remove fine particles and protozoa oocyst (e.g. giardia).   The first bank of cartridges is 1 um nominal and the second bank is 1 um absolute

Ultra-violet sterilisation unit – acts as an additional barrier against protozoa contamination.

pH adjustment is used to reduce the corrosive potential of the water to plumbing.

Chlorine addition for disinfection – to ensure there are no microorganisms present in the water distributed to the reservoir.

The water is then transferred to the 1.2 million litre capacity reservoir.

The supply zone extends from Oxford and Saunders roads to Hampton and Brophy roads and includes the Okato township. These rural properties supplied are either metered or have a restricted flow connection.