In a statement this morning, the Central Otago District Council said the precautionary advisory had been issued for residents connected to the Maniototo towns' water supplies, while upgrades were under way for both treatment plants.
The council said both towns' water treatment processes used chlorine to remove any risk of bacteria in the water supply, but they did not have a treatment barrier for protozoa - microscopic organisms, such as cryptosporidium and giardia, which can enter the water from animal faeces.
If present, protozoa can cause gastrointestinal illness such as vomiting and diarrhoea. Babies, young children, pregnant women, the elderly and people who have weakened immune systems are more at risk of illness.
CODC Group Manager - Three Waters Julie Muir said the council had approved the procurement of water treatment plant upgrades in January. The new treatment equipment was being prefabricated off-site and would be relocated when ready for installation. The upgrades were expected to be completed by December.
She said the treatment plant upgrades included the addition of filtration and ultraviolet treatment systems.
"These will supplement existing treatment processes to deliver safe drinking water that meets New Zealand Drinking Water Standards.
"The UV treatment will eliminate protozoa risks and the filtration system will improve the resilience of these supplies and enable them to continue operating in a wider range of weather conditions.
“There has been no change to the water supply on these schemes. However, the continued absence of protozoa barriers presents a risk to public health,” Ms Muir said.
“We understand this advisory will be an inconvenience for residents, and council is committed to providing monthly progress updates to the community on the upgrades.
"Taking this step will help protect the health of our communities until the new treatment systems are in place. Boiling water is an effective way to remove the risk of illness caused by protozoa.”
Health Information
The source water for the Patearoa and Ranfurly schemes comes from the Sowburn and Eweburn rivers. These are surface water sources that may be accessed by animals. If animal faeces enter the water, protozoa may be introduced into the supply, posing a potential health risk.
Residents connected to the Patearoa and Ranfurly water supplies must boil all water used for:
Drinking water
Brushing teeth
Preparing food
Washing fruits and vegetables
Making ice, baby formula, juice and cold beverages
How to boil water for drinking:
Bring water to a rolling boil (where bubbles appear 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 it into a clean container with a lid.
Refrigerate until needed.
Residents with well-maintained, high-quality cartridge filters followed by ultraviolet disinfection units that supply their entire house do not need to boil their water.
