We treat all our public water supplies in accordance with New Zealand Drinking Water Standards. We use a multi barrier approach to water treatment and monitor our supplies to make sure our water is safe to drink.
What is a Boil water notice and why would Council issue one?
A Boil water notice is an additional safety measure that can be used to protect public health and prevent illness from potentially contaminated drinking water. It would be used in situations where treatment processes or distribution systems are compromised and the drinking water could be contaminated. Boiling water is very effective at killing all disease-causing micro-organisms (e.g. campylobacter, giardia, cryptosporidium) in drinking water.
The Havelock North drinking water contamination event brought a national focus to drinking water safety in New Zealand. We’ve been carrying out a range of work with Regional Public Health to make sure your water supply remains safe to drink.
As part of our work with Regional Public Health, we’ve identified that during prolonged flooding events, there’s a very low risk to the quality of water supplied to Hautere/Te Horo residents. We have been in touch with residents on the Hautere/Te Horo water supply about this and what it might mean for them in the future.
It’s important to note that residents don’t need to do anything now. We monitor the water continuously and if there is any need for you to boil water we will communicate this to you at the time it’s required. A boil water notice will only be issued after consultation with Regional Public Health.
The Hautere/Te Horo water supply is unique in Kāpiti because the water comes from bores that are closely connected to the Ōtaki River. The water we take from the bores can take less than a day to travel to the bores from the river. Other bores across the District aren’t as directly linked to rivers so it takes longer for the water to travel through the ground. For example, the water in the Ōtaki public supply bores can take 13 months to travel there, and this natural filtering is a very effective first barrier that filters micro-organisms and turbidity.
While the ground water taken from the Hautere bores is also initially filtered by this natural barrier, there’s still a slight chance micro-organisms could get through this first natural barrier. That’s why we have treatment processes that kill anything that could get through and have advising residents about this and what it might mean for them in the future.
We take water from two bores alongside the Ōtaki River for the Hautere/Te Horo public water supply. When the Ōtaki River floods, the water can get so turbid (dirty-looking) that we can’t be 100% confident that this treatment plant will kill all the micro-organisms that could be in the water.
All our water supplies are continuously treated with high-intensity ultra violet (UV) light and chlorine to kill any micro-organisms (bacteria, protozoa and viruses) that might be in the water. We monitor these systems continuously and alarms are raised if something isn’t right.
The high-intensity UV light kills all bacteria and protozoa however it’s this process that can have reduced effectiveness during flooding events. The chlorine kills bacteria and viruses, but it doesn’t kill protozoa.
While we can manage this over a short period of time, during prolonged flooding events it’s important that additional measures are available to keep drinking water safe. So as a precaution, when the Ōtaki River is in flood, we might need to advise customers on this supply to temporarily boil their water to ensure it remains safe to drink.
This is a precautionary approach as our testing of the bore water hasn't shown any evidence of protozoa.
Protozoa are parasites found in the gut of infected people and animals. The protozoa associated with human illness are giardia and cryptosporidium. People infected with cryptosporidium or giardia usually get diarrhoea. Some people can get very sick from cryptosporidium or giardia, usually due to weakened immune systems. Visit the Health Protection Agency's website for more information.
If there was a risk to public health from reduced treatment effectiveness or potentially contaminated drinking water, we’d work closely with Regional Public Health, and clearly communicate with affected residents.
If a Boil water notice is issued, people should continue to boil their water until advised the water is safe again. We’d monitor the situation and risks and keep people informed with the latest updates through our website and other media.
Boiling water is very effective at killing all disease-causing micro-organisms (e.g. campylobacter, giardia, cryptosporidium) in drinking water and can prevent illness from drinking potentially contaminated water. Babies, young children, pregnant women, the elderly, and people who have weakened immune systems are more at risk of illness from drinking potentially contaminated water.
Pets and livestock can usually drink untreated water and we don’t expect animals to be at risk during a boil water notice.
We have plans to improve our water treatment plant processes to remove turbidity. These upgrades are part of a drinking water safety and resilience programme currently planned for 2018-22.