Dunedin boil water notice update

Dunedin (Thursday, 17 August 2017) – Initial water test results received last night from samples taken while the DCC was flushing the system show clear bacterial results for the parts of Dunedin affected by this week’s water quality issue.

However, people in the affected area should continue to boil their drinking water until further notice, almost certainly now until Saturday.

DCC Chief Executive Sue Bidrose says last night’s results measured the level of bacteria (e.g. E. coli) in the water at the time the samples were taken – about midday on Tuesday– after flushing of the system had started. Those results were within normal safe drinking water standards.

The DCC needs three days of clear bacteria test results, plus one clear protozoa test, before it can lift the boil water notice.

Dr Bidrose says the DCC is still waiting for results of protozoa (e.g. cryptosporidium, giardia) testing. It needs one clear protozoa test from the affected network before it can lift the boil water notice.

The process for protozoa testing is more complex and takes longer. A 20L sample of water needs to be carefully reduced to 0.5ml to maintain the integrity of the sample and then meticulously analysed under a microscope for some hours.

“It now looks like we expect to receive the results of this test late Saturday,” Dr Bidrose says.

“We have also taken water samples from the Ross Creek reservoir, so we know what might have entered our pipes. These results, which we now expect to receive tomorrow, will not affect the boil water notice, but will tell us what we might be looking at from a public health perspective.

“It is important to note that this water was diluted by treated water in the system and the test is a ‘worst case’ result.

“We will release all results to the public as soon as we get them,” she says.

Dr Bidrose says DCC business advisors and environmental health officers are available to help with advice about business continuity, and food preparation and safety. Concerned businesses should call 03 477 4000 for further advice. Information is also available atwww.dunedin.govt.nz/boil-water-notice.

Drinking water is available from water tankers at various locations around the city.

Untreated water entered the treated water supply on Monday afternoon when the water level in the Ross Creek reservoir was lowered to help with work. DCC plans and maps didn’t show a connection into the treated water supply so a valve was turned on to empty water from the dam. However, this has been proven to be incorrect, resulting in untreated water entering the treated supply.

Staff acted immediately when this was identified on Tuesday morning, closing the valve and flushing the affected water pipes. The network in the affected area has been flushed with twice its volume of treated water. Wednesday’s focus was on flushing the dead ends of the network after the main pipelines were cleared on Tuesday. Best practice is to flush with three times the volume of the pipes, so the network is being flushed again today. The DCC is receiving advice from an international drinking water quality expert, Dr Colin Fricker.

Boil water notice
All residents and businesses in the following areas are advised to boil all drinking water until further notice. This is due to an issue with water quality and is isolated to the north end of the city. The notice applies to parts of the central city, Leith Valley, Woodhaugh and the tertiary precinct. An interactive map of the affected area is available atwww.dunedin.govt.nz/boil-water-notice.

• Tap water in affected areas must not be used for drinking, making up baby formula and juices, making ice, washing fruits and vegetables, or brushing teeth.
• Please boil ALL drinking water before use. Zips do not boil water sufficiently. Water needs to be through a rolling boil for at least one minute and filtered water should also be boiled for at least one minute.
• If you’re in an affected area, please flush run your taps for 10-15 minutes if you haven’t already done so. This will flush the water and will help with the cleaning process.
• If you have a hot water cylinder, please empty it if you haven’t already done so – it can then be refilled with clean water.
• If you are in an affected area and have water that you have drawn from the tap since Monday morning, please tip it out and do not drink it.
• As a precaution, please use hand sanitiser after washing your hands. Care should be taken with bathing and showering so that water is not swallowed.

Water tankers
Eight water tankers are available for businesses and the public. People wanting to collect water should bring their own containers. These should not be rinsed with tap water before being used to store clean water.

• The Octagon (available throughout the night)
• Corner Dundas Street and Montgomery Avenue (available until 10pm, returns6am)
• Outside Otago Museum (main entrance) (available until 10pm, returns 6am)
• Outside George Street Normal School (available until 10pm, returns 6am)
• Outside the Oval BP forecourt (available until 10pm, returns 6am)
• Outside Hunters Furniture, Cumberland Street (available until 10pm, returns6am)
• Outside Emerson’s Brewery, Anzac Avenue (available until 10pm, returns6am)
• Logan Park High School car park, Butts Road (available until 10pm, returns6am)

More information, including a map of the affected area, is available atwww.dunedin.govt.nz/boil-water-notice.

Updates and information are also available at www.facebook.com/DunedinCityCouncil.

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