Raetihi water safe despite taste, smell concerns

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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.

She says the water is safe to drink and will not cause people to be ill.

"Raetihi's reticulated drinking water is treated, tested daily and is safe to drink. Council's water contractor, Veolia Water, takes water samples daily for testing from alternating points around the Raetihi reticulated network as well as a weekly test for E.coli bacteria."

Testing checked free available chlorine (FAC) which is a measure of the chlorine left in the water after treatment; the pH level (which is a measure of alkalinity and acidity); water temperature (which affects the pH level) and turbidity (which is a measure of organic material in the water).

The other major weekly test checks for E.coli bacteria. E.coli is an indicator species of bacteria that lives in warm blooded animals and can cause diarrhoea, dehydration and vomiting.

"The E.coli test requires the laboratory to see if a culture grows in the water sample, which takes 48 hours, so 'instant' results are not possible," she says.

No positive E.coli had been found in the Raetihi treatment plant since 2010.

Ms Westcott said removing taste and odour was not a simple process and required a full treatment system which, even then, may not always remove it all.