Lake Wakatipu is used for Queenstown's town water supply. Photo: RNZ / Marika Khabazi
Hundreds of thousands of New Zealanders could be drinking water at risk of parasites such as cryptosporidium, according to the national water regulator.
Taumata Arowai has named a total of 84 water suppliers that do not have sufficient UV filtering facilities to protect against protozoa organisms.
The list affects approximately more than 310,000 people across a total of 27 councils, with more than half of this number concerning residents in Christchurch.
It comes off the back of Queenstown's cryptosporidium outbreak with at least 60 confirmed cases in the resort town.
Two water suppliers, listed as Christchurch and Wainui, have been identified by the regulator as lacking in a protozoa barrier.
The suppliers service nearly 169,000 Christchurch residents.
Other councils significantly implicated include the Queenstown Lakes, Waimakariri, the Grey district and Gore.
Residents and businesses have been forced to boil their water for two weeks following an outbreak of the gastro bug.
The Queenstown Lakes District Council lifted the notice for some suburbs and nearby Frankton earlier today, after isolating the water supply from the Kelvin Heights treatment plant, which already has an effective barrier against the bug.
Councils are responsible for providing drinking water to around 83 per cent of the population.
Taumata Arowai's head of regulatory Steve Taylor said the organisation wrote to all council, government, and private suppliers that shared the "same characteristics" as Queenstown last week.
"Now that we have assessed the information provided, we have identified 27 council suppliers across Aotearoa that have drinking water treatment plants that should have a protozoa barrier in place, but have told us that they don't."
He said further correspondence was sent on Thursday, issuing a deadline of 30 June 2024 for councils to confirm a funded plan.
Surface water suppliers have until 31 December 2024 to install a protozoa barrier, while bore water sources had a further 12 months to do the same.
"In our letter, we have clearly set out our expectation - that drinking water suppliers must meet the legislative requirements of the Act and continue to provide safe drinking water to their communities," Taylor said.
"We are considering what regulatory action is required should suppliers not respond satisfactorily within the timelines set out in our letter.
"Shortly we will be writing to council and government suppliers we have identified without other required forms of treatment, such as residual disinfection in the distribution network, to set out our expectations of compliance for these matters."
The Christchurch City Council's head of three waters Brent Smith said it was awaiting correspondence from the regulator.
"Once we have received and reviewed the letter, we will be better placed to provide comment.
"However, we are already in the process of establishing a programme of work to achieve compliance.
"This includes the current intensive testing programme to meet the Class 1 criteria. This programme is well underway and so far has achieved good results."
Lifting of boil water notice good news for Queenstowners
Queenstown businesses were pleased to have the boil water notice partially lifted.
Hilton South Island general manager Chris Ehmann welcomed the removal of the boil water notice, saying it was helpful for their Kelvin Heights hotels.
Hilton South Island general manager Chris Ehmann is excited to have the boil water notice lifted. Photo: RNZ / Tess Brunton
"We're very excited to start the day without boiling water so I think onwards and upwards.
"I hope that they get it all sorted out for the rest of Queenstown so everyone can have that restriction lifted."
It would mean an easier time for staff who have had to pre-boil water to clean produce, make coffees and any cooking, he said.
Pete Dodds from Francesca's Mobile Pizza said they had been filling up their water tanks in areas unaffected by the notice.
They were parked in Frankton on Thursday, and said he hoped the partial lift would encourage more people to visit.
"Definitely making life a little bit easier for everyone, even just like general washing up. But hopefully it will start to bring some more numbers in."
Francesca's Mobile Pizza owner Pete Dodds says it's welcome news that they can fill up their water tanks closer to home. Photo: RNZ / Tess Brunton
Sara Irvine from Queenstown Airport said they installed their own protections including adding filters in all their kitchens during the outbreak.
"We have also made sure that we have really high quality UV filters available for people to fill their water bottles.
"So now that the boil water notice is lifted, which is great news for this area, we actually do have the protections in place that should this happen again, we have excellent filters in place."
The mayor of Waitaki said drinking water in about five percent of his district was not protected against Cryptosporidium.
Gary Kircher told Checkpoint about 1300 properties in the community were supplied water that did not have the required UV filters.
Kircher said these residents were under boil water notices.