Algae in the Tutaenui Dam has caused an unusual taste and odour in the Marton water supply over the past few days.
However, the water remains safe to drink, Rangitīkei District Council operations manager Andrew van Bussel says.
"We've got a full, conventional treatment plant which is fully compliant, and the drinking water is also fully compliant," van Bussel said.
"It has to meet all the standards otherwise we get into a fair bit of hot water, so to speak."
Van Bussel said the council dosed activated carbon into the water supply to "absorb some of that taste and odour issue" and had adjusted the doses again after complaints from the public were made.