A water shortage and a treatment mistake in the Rangitīkei town of Marton has forced the district council to bring in a water tanker to provide clean drinking water.
The treatment issue resulted in brown, foul-smelling tap water for the town's 5000 residents.
The tanker stationed next to Marton Memorial Hall would remain until water levels return to normal, which was expected to be Friday evening, Rangitīkei District Council chief executive Ross McNeil said.
The town's reservoir is at low levels and households and businesses have been asked to conserve as much water as possible.
The discoloured water supply was safe to drink, Mr McNeil said, but there was the potential for it to stain clothing or other materials.
Usually the township's untreated water contains high levels of a dissolved mineral called manganese, but this was mostly removed with chlorination. But in this case the chlorination level was not high enough, he said.
Council staff had been flushing pipes in the township, and residents were also asked to run their taps, especially hot taps, to help flush the discoloured water away.
The council said it would consider reimbursing any properties with a noticeably higher water charge than usual. And anyone with stained items should contact the council and their insurer.