Brown water 'an aesthetic issue' but safe to drink - Timaru council

11:21 am on 21 January 2022

Timaru has had discoloured drinking water for close to a month, with some residents also reporting their water smells.

Tap water

Photo: RNZ / Rebekah Parsons-King

Local Sharleyne Diamond said the discolouration was not always clear in a glass, but was quite noticeable in larger volumes.

"I could see it in the bottom of my sink or in the bath ... when I ran it against the white I could see that it was brown."

She also described the water as having "floaties".

"I did notice the other day when I was drinking the water [that] there were little bits of something in it."

But despite the colour, head of infrastructure at Timaru District Council, Andrew Dixon, said since people first reported the brown water, it has been safe to drink.

"We did a thorough testing of the [water system] to make sure that, first and foremost, the water was safe to drink," he said.

"And those tests came back proving ... there's no issue, it complies with the drinking water standards and is safe. So it's really an aesthetic issue."

Taumata Arowai is New Zealand's new national water service and regulatory leader, Peter Wood, explained sometimes drinking water can be deceptive.

"So you can certainly get discolouration, tastes, odours, smells, staining of laundry from a variety of causes, depending on the water source and what's going on with the water supply," he said.

"Those things don't necessarily mean that the water is unsafe to drink."

Wood also warned the opposite was also true.

"You might find water that looks and smells and tastes really good but it's not safe."

Andrew Dixon said the council believed a non-toxic cyanobacteria, or algae, in the secondary water source was causing the discolouration.

Following heavy rain in December, the main water source at Pareora River was not able to be used, so the council switched to a secondary water supply at the Opihi River.

Dixon said this was where the problem lay.

"There was a very high algae content from one of the test results coming from the Opihi source.

"And during the treatment process, that algae may have caused some of the discolouration," he said.

Water New Zealand technical manager Noel Roberts said algae may become more of a problem in the future due to climate change.

"Discoloured water from algae is quite unusual," he said.

"Taste and odour issues from algae is quite common."

"And it is very much a growing concern in New Zealand ... last year was our warmest year in a hundred years."

Though Timaru District Council appear to be managing it.

Some residents have been using water from tankers and there is a sprinkler ban in place for the town as the council tries to reduce demand for tap water, while it refills the reservoirs from its usual Pareora River source.

Dixon said it was filling by about four percent a day, on average.

Sharleyne has already noticed a change in what has previously been voted as New Zealand's best water.

"There's a definite improvement I would say.

"I showered in it right from the get-go, it didn't really bother me. I don't have a funny tummy or anything," she laughed.

"I wasn't too worried about it. I've just gone off what the council have said and they said it was safe."

Taumata Arowai's Peter Wood believed more education on where water comes from could help protect sources.

Timaru District Council has been vocally against the proposed Three Waters reforms, and was one of three councils which filed a claim against the government in Wellington High Court in November last year.

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