The Government’s Water Services Authority – Taumata Arowai, now requires the Council to manage the possible public health risk that exists due to the potential for protozoa to be present in the supply. Protozoa, such as Cryptosporidium and Giardia, are not removed by chlorine and therefore if they are present, unlike bacteria such as Salmonella and Campylobacter, they will not be removed and therefore could potentially cause illness through consumption of drinking water. Boiling water is an effective treatment for both protozoa and bacteria.
Everyone who uses the water supply is recommended to follow this advice:
Boil all your water for the following purposes:
- Drinking water
- Food preparation
- Mixing cold beverages
- Utensil washing
- Brushing teeth
- Pets
- Ice making
How to boil water for drinking:
- Bring water to a rolling boil (where bubbles appear in the centre and do not disappear when the water is stirred) for one minute or boil a full electric jug until it switches off.
- Cool the water (do not use ice cubes to do this) and pour into clean container with a lid.
- Refrigerate until needed.
If you have a high-quality cartridge filter with a 5 micron or less pore size, followed by an Ultraviolet disinfection unit, which are well-maintained and supply water to your entire house, there is no need to boil your water.
We wish to assure customers that there has been no change to the water quality or public health risk within the scheme and that this notice is in response to the expectations of the Authority. We do acknowledge however that without a protozoa treatment barrier (such as ultraviolet light disinfection) a low protozoa risk may exist, given that the source water for the scheme is from relatively shallow groundwater bores that have the potential to be influenced by surface water from time to time.
Protozoa, and bacteria, are disease-causing organisms which can be carried by a wide range of animals, including humans, and can be present in surface and shallow groundwater if contaminated by animal or human faeces.
There is no treatment method other than chlorination on the Redwoods schemes and this is not capable of removing protozoa. Therefore, the Council can only manage the potential protozoa risk by asking customers to boil all water used for drinking, teeth cleaning, etc, at all times. Chlorination, for bacteria removal, and water quality monitoring will continue unchanged.
The Water Services Authority - Taumata Arowai has accepted this way of managing the protozoa risk until such time as the water provided to the scheme is treated to remove both bacteria AND protozoa.
The Council is currently implementing a project to combine the Redwoods 1 and 2 supplies into one with a centralised treatment plant near the existing River Road bores. This treatment plant will incorporate processes to disinfect both bacteria and protozoa with its completion anticipated to be mid-2027. The current Redwoods 1 (Golden Hills) and Redwoods 2 (O’Connors) water scheme configuration is depicted in this schematic:
