It will likely be ten weeks before a boil water notice can be lifted in central Queenstown, though suburban areas may face a shorter wait.

A boil water notice was put in place on September 18, after a cryptosporidium outbreak was identified in the town.

Two days later water regulator Taumata Arowai issued a compliance order requiring a protosoa barrier to be installed at the Two Mile intake, which provides drinking water to Queenstown.

Queenstown Lakes District Mayor Glyn Lewers said the council had secured UV disinfection equipment, an effective protosoa barrier.

It had an estimated completion date of December 8.

Medical Officer of Health Dr Emma Sherwood said the number of confirmed cryptosporidium cases in the outbreak had risen to 48 with 12 probable cases, and 3 under investigation, as of 10am on Friday.

A source of infection had not been identified and investigations were ongoing.

Public Health were aware that some of the cases were the result of secondary infections – where people were getting it from people they lived or worked with.

“It is very important that everyone practise good hand hygiene to stop the spread of crypto to other people.

“Wash your hands with lots of soap and water for at least 20 seconds and then dry them thoroughly on a clean towel,” she said.

Council general manager of property and infrastructure Tony Avery said the council had submitted a plan to Taumata Arowai to isolate the Kelvin Heights water supply network, which supplies water to the Frankton area and Kelvin Heights.

It already had an effective protosoa barrier in place.

“[Council] is working hard to see normal service returned as quickly as possible and working with Taumata Arowai QLDC is targeting to lift that before the end of the school holidays,” he said.

The school holidays finish on October 6.

Frustrated hotel and restaurant workers have been spending hours making sure guests are up-to-date about the boil water notice and implementing changes to comply.

The council has supplied water tankers in the central business area for individuals and businesses to source drinkable water.

Avery said the UV equipment that would be used at the Two Mile plant would be a temporary solution as the correct sized equipment was not available.

Larger UV reactors had also been ordered and once they arrived they would be installed and the temporary equipment could be used on other water supplies, including Western Wānaka, Beacon Point in Wānaka, and Luggate.

“While we know people will be looking for more detailed steps, which we will be providing soon, we wanted to provide an indication of the timeline to resolve the current situation as soon as we had that date,” Avery said.

Lewers said it was frustrating that the boil water notice remained in place, particularly in areas sourced from the Kelvin Heights intake.

The council was working with Taumata Arowai to find ways to lift the notice across the network “as soon as possible and well ahead of December 8,” he said.

Testing of the water supply in the affected area continued to return negative results for the presence of cryptosporidium or other signs of contamination.

The extensive sampling and testing programme was ongoing.

In light of the Queenstown outbreak academics at the Public Health Communication Centre called on the central government to ensure water regulator Taumata Arowai was empowered and resourced to protect source water, on Friday.

They also wanted more clarity on responsibilities for safe drinking water across government agencies.

While the water source was considered the most likely risk for outbreaks, it was notable that cryptosporidiosis cases in New Zealand always peaked in September and October, coinciding with the spring lambing and calving seasons.

There have also been previous reports of wastewater and sewage overflows into Lake Wakatipu and rivers near Queenstown, the academics said.

Other potential sources included recreational water, or food and beverages.

Climate change and intense rainfall events also increased the likelihood of water contamination.

“This factor was underscored by the extreme weather and flooding in Queenstown that occurred last week (though after the start of this outbreak),” they said.

In the meantime, the Department of Conservation some local walking tracks remain closed after last week’s record rainfall.

The Lake Sylvan Track, near Glenorchy, and the Mt Crichton Loop, near Queenstown, were closed due to large washouts and damaged bridges.

The Dore Pass carpark and Mackay Creek Campground on the Milford Road were closed due to washouts, and Freeman Burn Hut in Fiordland was closed due to the risks posed by a dam which has formed upstream of the hut.