UPDATE 2: All drinking water must be boiled in Martinborough until further notice

4pm, 11 April 2019

A boil water notice was issued for all users on the town water supply on Tuesday 9 April, following positive results for E. coli.

South Wairarapa District Council (SWDC) advises that all drinking water in Martinborough must be boiled before being used for drinking, making up formula, juices, ice, washing fruits and vegetables, and other cooking needs, or brushing teeth.

Acting Chief Executive Jennie Mitchell says, “as this is the second time we’ve had to issue a boil water notice this year, we can totally understand the frustration and inconvenience this is causing residents.”

Investigation into the UV disinfection system rules it out as the cause of contamination for this April event. In February, a malfunction in the UV disinfection system, which resulted in untreated water being pumped into the water supply network, was found to be the probable cause of contamination.

Ms Mitchell says, “while it is good news that the UV system is working well, this means we need to carry out a systematic risk assessment of the rest of the network to find the source of contamination”.

Test results received today for samples taken before chlorination confirmed the presence E. coli at the reservoir, but all other samples taken around the town were clear.

“Given the test results received today, Council, working with Lutra, Regional Public Health and Wellington Water, is focusing its investigations at the reservoir. In addition, we will be checking backflow mechanisms to private properties to help isolate the source of contamination.

“While this all takes time, it is essential.

“This latest event demonstrates the need to have more than one barrier in place to ensure safe water,” says Ms Mitchell. “Protecting public health is our highest priority, and Council will be giving the highest priority to the work of providing a safe water supply to the community for the future,” says Ms Mitchell.

Timeline of events

February incident

  • A boil water notice was issued for the town on 1 February and remained in place for three weeks.
  • Investigations into the probable cause identified the likely cause to be a malfunction in the UV disinfection system.
  • The UV disinfection system was fixed so it was working as per the manufacturer’s specifications.
  • Working with advice from Wellington Water, the town water supply network was systematically checked for potential sources of contamination, and any identified risk points were addressed, including replacing hatches on some of the storage tanks.
  • Flushing of the water supply using water compliant with drinking water standards was completed on 17 February. Subsequent testing of the water for three days following the flush received clear results for E. coli and the boil water notice was lifted on 21 February.
  • Since the notice was lifted, Council has increased water sampling and testing, both in terms of the number and frequency of sites, in addition to the online monitoring of the data from the UV disinfection system.

April incident

  • On 9 April, low levels of E. coli were detected in two routine water samples taken at the reservoir and at Shooting Butts Rd; all other samples taken around the system came back clear of E. coli.
  • In consultation with Regional Public Health, a boil water notice was issued at approximately 6pm on 9 April.
  • The boil water notice was communicated by letter drop, load speaker announcements, electronic and corflute message signs, print and radio media, ratepayer email list, the Martinborough Business Association, Lions and sports clubs.
  • Wharekaka Rest Home, Martinborough School, kindergartens, day cares and medical centre also received direct communication.
  • Further water samples taken on the evening of 9 April were driven to Upper Hutt for testing.
  • The water network near the sites where the positive samples were taken was chlorinated on the night of 9 April.
  • On 10 April, water bladders were installed to provide alternative, safe water sources at Wharekaka Rest Home, the Square, Rugby Club, Waihinga Centre, Martinborough School and Martinborough Golf Club.
  • On 10 April, Council, Lutra, Wellington Water and Regional Public Health started daily incident management meetings.

New information today

  • On 11 April, the UV disinfection system was ruled out as the cause of contamination in this incident.
  • On 11 April afternoon, results for the water samples taken at the reservoir pre-chlorination on the evening of 9 April confirmed the presence of E. colii; all other samples taken around the town were clear.
  • To date, Regional Public Health and Wairarapa DHB are reporting no confirmed illness in association with this event.

There is a risk of getting sick from drinking the water without boiling, especially for vulnerable people. Babies, young children, pregnant women, the elderly and people who have weakened immune systems are more at risk of illness. If you get diarrhoea, vomiting and/or a fever, get advice from your doctor or contact Healthline (0800 611 116).

The boil water notice is in effect until further notice.

Next update: 2pm Friday 12 April, or earlier if required.

How to boil water for drinking:

  • Boiling will kill all disease-causing organisms.
  • Bring water to a rolling boil (where bubbles appear in the centre and do not disappear when the water is stirred) for one minute or boil a full electric jug until it switches off
  • Cool water (do not use ice cubes to do this) and pour into clean container with a lid
  • Refrigerate until needed.

For further information, contact SWDC on 06 30 69611 at or go to swdc.govt.nz/Martinborough-town-water-situation, for future updates, background information and FAQs.

ENDS

Media contact

Amy Wharram

021 252 2863

South Wairarapa District Council