CDC pushes to raise water standards

Gareth Phillips
Gareth Phillips
Clutha District Council  is working to increase compliance with drinking water standards following a succession of E. coli warnings this summer.

Council operations manager Gareth Phillips announced the drive during Thursday’s  CDC service delivery committee meeting in Balclutha.

He said recent positive tests for E. coli had led to an elevated number of precautionary boil water notices for many of the district’s rural water schemes.

Council staff were receiving advice from the Southern District Health Board’s drinking water assessor in regards to public safety during this time, although the risk of infection from drinking the water was relatively low, he said.

"If we look at the trigger results we’ve been getting, they’re in the 1 to 5 bacteria per 100ml range which, although non-compliant, is still at the bottom end of the scale.

"By comparison, where a known issue of contamination is identified you might expect a result of 50,000 upwards."

He said any level of non-compliance was unacceptable, however, and the council was adopting a two-pronged approach to address the problem.

"Often these sorts of problems are caused by the existence of biofilm [bacterial] build-up on the inside of pipes, which can reduce chlorine levels in the local supply over time.

"Another possible cause is unconsented attachments to the network, which can contaminate certain branches locally."

Contractors had been asked to increase chlorine levels where appropriate, and extensive sampling on branches was also being carried out to identify specific problem areas.

In addition to practical steps to improve water quality, the council was also working to improve its notification of end users.

"Recent issues have also highlighted gaps or confusion within communications.

"Complex rural and urban schemes mean it’s not always clear to consumers when they are affected by a boil water notice.

"Staff have been focusing on clarifying our messages using maps and multiple media messaging."

Mr Phillips told councillors he was confident the steps announced would continue to "keep people safe".

richard.davison@odt.co.nz

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