By Chris Morris

Dunedin faces days of disrupted water supplies following the discovery raw water has been entering the drinking supply.

It was confirmed this morning untreated "raw" water being spilled from the Ross Creek Reservoir had been finding its way into the drinking water network since Monday afternoon.

The discovery was made after a spike in complaints of discoloured water coming out of city taps about 9.30am, and the reservoir's spill was stopped by 10am.

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A hospitality worker gets water from a tanker in the Octagon. Photo / Chris Morris, Otago Daily Times
A hospitality worker gets water from a tanker in the Octagon. Photo / Chris Morris, Otago Daily Times

But by then, the raw water had been delivered across a large swathe of the city, from the CBD to North Dunedin, Leith Valley and Woodhaugh, and any area in the central city between the town belt and the harbour.

A boil water notice was issued this morning, covering 1721 residential properties and 826 commercial properties, Council infrastructure and networks general manager Ruth Stokes told a media conference this afternoon.

Council chief executive Sue Bidrose said a fully-treated water supply was expected to be restored by mid-afternoon, but the boil water notice would remain in place until late on Friday at the earliest.

It could only be lifted 24 hours after three days of clear water test results, she indicated.

In the meantime, people covered by the notice were being urged to discard any stored water and items, such as lettuce, which could have been washed with potentially contaminated raw water, she said.

Businesses were also being encouraged to discard food that could be contaminated, and make an insurance claim to cover the cost, she said.
And people returning home should also run their taps for up to 30 minutes, to flush any remaining raw water from their pipes.

The first water test results were not expected until tomorrow, and Dunedin Hospital was yet to report any presentations of people with diarrhoea or vomiting after drinking contaminated water.

The Dunedin City Council's boil water notice has resulted in a rush of people buying bottled water. Photo / Louise Frampton, Otago Daily Times
The Dunedin City Council's boil water notice has resulted in a rush of people buying bottled water. Photo / Louise Frampton, Otago Daily Times

Earlier today, it was confirmed the council had activated its emergency operations centre to handle the scare, as it raced to flush potentially contaminated water from the city's drinking supply.

Dunedin Hospital has also activated its own EOC, and was relying on water tankers arranged by the council to supply fresh drinking water, Mrs Stokes said.

Eight other water tankers have been dispatched to other parts of the city, including to George St Normal School and Logan Park High School, both in the affected area, she said.

The boil water notice has already resulted in a rush of people buying bottled water.

The raw water released from Ross Creek had entered the city's drinking network through old pipe - no longer recorded on council plans - just below the reservoir.

The raw water came from a "protected catchment", and would have been diluted as it mixed with the city's treated drinking water supply, but the health risks were not yet known, she said.

"In some parts it would have been reasonably diluted, but you're basically drinking water that's the equivalent of drinking it straight out of a stream or lake.

"But at the moment I can't tell you with any certainty what risks are associated with that water."

By lunch time the shelves at Dunedin central's Countdown were almost empty of bottled water. Photo / David Loughrey, Otago Daily Times
By lunch time the shelves at Dunedin central's Countdown were almost empty of bottled water. Photo / David Loughrey, Otago Daily Times

Southern DHB Emergency Operations Centre Incident Controller Jenny Hanson said some elective procedures had been postponed as a result of the issue.

Staff had been advised not to use or drink the water and bottled water and a tanker were supplying the hospital, Ms Hanson said.

Orderlies were delivering drinking water to all areas of the hospital, she said.

"We're following infection prevention and control protocols to ensure we keep our patients safe including additional distribution of hand gel and hand hygiene information.

"Some elective procedures have been postponed today.

"Currently we are reviewing elective procedures for tomorrow based on current high acute demand.

"Any affected patients will be contacted by the hospital," she said.

Its emergency department was busy and the public were asked to keep ED for emergencies only.

Dunedin City Council contractors flush water out of a water main on Malvern St in an effort to clear the contamination. Photo / Craig Baxter, Otago Daily Times
Dunedin City Council contractors flush water out of a water main on Malvern St in an effort to clear the contamination. Photo / Craig Baxter, Otago Daily Times

Public Health South was carrying out surveillance for gastroenteritis (vomiting and diarrhoea), but so far had not observed an increase in cases.

"Our staff are doing a fantastic job and we also thank our patients for their understanding.

"We are reviewing the situation on a regular basis and will provide updates if required."

By lunch time the shelves at Dunedin central's Countdown were almost empty of bottled water.

The University of Otago has sent text messages to students warning them to not drink water from the tap.

Some schools have sent emails to parents reassuring them children were not being allowed to drink water at school today.

Central Dunedin cafes have stopped serving coffee and any other items containing tap water.

A map of areas part of the Dunedin City Council's boil water notice. Graphic / Dunedin Council
A map of areas part of the Dunedin City Council's boil water notice. Graphic / Dunedin Council

Dunedin council media update

Members of the Dunedin City Council and Civil Defence team gave an update to media this afternoon.

A spokeswoman said staff had gone out to the Ross Creek Reservoir yesterday afternoon to carry out some work.

"We wanted to empty some water out of the [creek]. The reservoir is undergoing refurbishment of the dam wall and it's currently at its most risky state in that process."

Flooding in the area about three weeks ago had resulted in the water level of the reservoir higher than what authorities would like, so the process of lowering that, in order to continue refurbishment work, was due to start.

"Staff opened a valve they knew led to venting of the Ross Creek Reservoir into the stream so that we could slowly, over time, begin to reduce the level of water in the reservoir,'' she said.

"Unfortunately, it turned out that valve vented water from the reservoir into some pipe-work that [according to] all of our paperwork [indicates] was shut down and disestablished 30 years ago and actually let it into the city's water supply.''

The spokeswoman said they had had a couple of calls come through yesterday from members of the public complaining about the state of their tap water.

Initially, it was thought that it was due to cast iron pipes.

However, by this morning, the number of calls had peaked, she said.

"The guys had a closer look and at that point they realised that water wasn't going into the stream - it was in fact going into the town's pipes.''

That pipe was shut down immediately after the problem was identified, which was about 9.30am today.

By 10am, the affected pipe had been secured and no raw water has entered the treated water system since.

There have been nine teams of people entering the city to carry out work. Warning notices were also issued to residents, urging locals to boil all drinking tap water.

"They have been opening hydrants and drawing the water out of the system,'' a member of Civil Defence said at a media conference.

"We're close to having all of the water out of the system now.''

Up to 1721 residential properties and 826 commercial properties are affected.

What you need to know

The warning

The Dunedin City Council this morning issued a boil water notice, warning residents in a large swathe of the city to avoid drinking water from the tap, or boil it, because of a water quality issue. The council has activated its emergency operations centre (EOC) as it races to flush potentially contaminated water from the city's drinking water supply.

Who is affected

The affected area stretches across much of the north of the city, including the CBD, North Dunedin, Leith Valley, Woodhaugh and any area in the central city between the town belt and the harbour.

How long is the warning expected to last

The boil water notice is expected to remain until Friday.

The risks

Council infrastructure and networks general manager Ruth Stokes said there was no certainty about the level of risk associated with the affected water.

"In some parts it would have been reasonably diluted, but you're basically drinking water that's the equivalent of drinking it straight out of a stream or lake."

The cause

The council says it appeared untreated raw water released from the Ross Creek Reservoir on Sunday had been able to enter the city's drinking water network.

Workers had begun releasing water from the reservoir into Lindsay Creek on Sunday, in preparation for work set to begin in the area. Complaints were received Monday night and this morning, prompting an investigation which found an old pipe - no longer recorded on council plans - just below the reservoir.

The pipe connected to the city's drinking supply, allowing raw water back into the network.

Where to get drinkable water

Eight water tankers have been dispatched to parts of the city, including to George St Normal School and Logan Park High School, both in the affected area.

A rush means finding bottled water at supermarkets may be difficult.

Here are the locations and times water tankers will be available:

• Cnr Dundas & Montgomery Ave, from about 2pm.

• Outside Otago Museum (Main Entrance) from about 2pm.

• Outside George Street Normal School from about 2pm.

• Oval BP forecourt from about 2pm.

• The Octagon from about 12pm.

• Outside Hunters Furniture Cumberland St from about 2pm.

• Dunedin Hospital

• The council says Dunedin Hospital has also activated its own EOC, and is relying on water tankers arranged by the council to supply fresh drinking water.

• The Southern District Health Board said Dunedin Hospital was operating as normal.