Naturally occurring growths of bacteria have prompted concerns about the taste and smell of Raetihi's tap water.
That's the word from the Ruapehu District Council after some locals were worried about the water currently drawn from the Makara stream.
Town supply had come from the Makotuku River but was switched to the Makara after the diesel spill last year.
Anne Marie Westcott, the council's environmental manager said the taste and odour issues did not pose any health risk and were the result of bacteria and algae growth in the stream.
Ms Westcott said the algal and bacterial growth was more prevalent at this time of the year when water flows were low, and were found in many Ruapehu waterways including the Makotuku River and the Whanganui River that supplies Taumarunui.