Dunedin boil water notice update #6

Dunedin (6pm, Thursday, 17 August 2017) – The Dunedin City Council is hopeful that the boil water notice for parts of Dunedin will be lifted late tomorrow.

Chief Executive Sue Bidrose says the DCC had needed three days of clear bacteria (e.g. E. coli) test results, plus one clear protozoa (e.g. cryptosporidium, giardia) test, before it could lift the boil water notice.

However, after discussions today with drinking water assessors and the Medical Officer of Health, it was established that because of the results to date and steps taken, the DCC could use its discretion to lift the boil water notice without a clear protozoa test. The protozoa test results will not arrive from the laboratory before the weekend.

“The best case scenario we are now working towards is receiving a third clear bacteria test late tomorrow, which would allow us to then lift the boil water notice,” says Dr Bidrose.

“In the meantime, people in the affected area should remain vigilant and continue to boil water until further notice.”

Dr Bidrose says the DCC has now received two days of clear bacteria test results from water samples taken from pipes in the affected area. Both sets of results were within normal safe drinking water standards.

The Southern DHB has this afternoon advised the public that the risk of contracting gastroenteritis (diarrhoea and vomiting) due to the water quality issue is low.

Public Health South’s monitoring of gastroenteritis shows that there has not been an increase in gastroenteritis in the Dunedin area. There had been no notified cases of campylobacter, cryptosporidium or giardia in the Dunedin area in the last 48 hours (to midday today).

Dr Bidrose says in anticipation of lifting the boil water notice, the DCC will tomorrow be providing information for affected businesses and residents on how to flush their water storage. This will help to remove any residual untreated water from their systems.

Reservoir test results
Dr Bidrose says initial results from water samples taken from the Ross Creek reservoir are encouraging.

Test results received today from the reservoir were taken on Tuesday and show E. coli was within normal range at three random sample sites and was elevated at one site. This is a ‘fail’ as drinking water, but is within swimming water guidelines which is as expected.

“What this means is that the quality of the untreated water which made its way into the water supply was at a level you could swim in but we wouldn’t generally recommend you drink.

“These results do not affect the boil water notice, but help tell us what was in the untreated water that entered the system and was delivered, diluted by treated water, to affected properties,” she says.

Results taken from water pipes in the affected area on Tuesday do not show evidence of any algal bloom.

All results are being made available on the DCC website at www.dunedin.govt.nz/boil-water-notice as soon as possible.

Further information and advice
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 at www.dunedin.govt.nz/boil-water-notice.

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. The pipes shown on the old plans as ‘decommissioned’ was today decommissioned.

Staff acted immediately when this was identified on Tuesday morning and closed the valve. They have been flushing the affected water pipes since.

Boil water notice
All residents and businesses in the affected area are advised to boil all drinking water until further notice: 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.

Locations of the tankers, and more information, is available at www.dunedin.govt.nz/boil-water-notice.

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

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