Residents in Queenstown and Frankton were told to boil their water from mid-September following confirmed cases of illness caused by the parasite cryptosporidium.
Investigations suggest the most likely source was human faecal contamination of the water supply and Queenstown Lakes District Council was ordered to upgrade its Two Mile treatment plant.
Queenstown Lakes District Mayor Glyn Lewers said the requirements of the compliance order issued by water regulator Taumata Arowai had now been met.
“[This] means everyone is able to return to using water straight from the tap for the weekend,” he said.
“Our infrastructure team has installed new UV reactors at Two Mile water treatment plant and these are now fully operational. All of the live network reservoirs have been inspected and cleaned, and the local network has been flushed.”
The council will provide an update shortly on its work to install UV treatment to remaining plants around the district, along with a permanent solution for Two Mile.