Should all New Zealand drinking water be treated?

To treat – or not to treat – that's the question facing Kiwis who drink pure, unchlorinated water.

Is the Hawke's Bay town’s scare a wake-up call for the rest of New Zealand? Source: 1 NEWS

The Havelock North water crisis has Water New Zealand suggesting a discussion needs to happen about whether councils should be making the decision on whether water should be treated.

Between 20 and 30 per cent of the country drinks untreated water – mainly in the Hawke's Bay, Christchurch and Lower Hutt.

Water New Zealand chief executive John Pfahlert says drinking water needs to be supplied to a quality where people can be confident it won't be polluted.

The Hastings District Council has warned residents they'll need to consider whether their water needs to be permanently chlorinated in the wake of the contamination which resulted in over 5000 people falling ill with a gastro bug and over 600 people contracting campylobacter.

That issue is set to divide the community, mayor Lawrence Yule admits.

He says he isn't a fan of chlorination but no-one wants to see another contamination scandal.

The Prime Minister says any move to mandatory chlorination would be "quite controversial".

The Hawke's Bay Regional Council has growing concerns about maintenance of water bores. Source: 1 NEWS

"You take Christchurch for instance, which has long prided itself if you like on its artesian wells and its unchlorinated water and I think they would be very concerned about any forced move by the Government to make the people of Christchurch drink chlorinated water," John Key said.

Mr Pfahlert told ONE News the inquiries into the Havelock North contamination needs to look at the issue, including whether small communities need help to install treatment plants.

"The Government, who imposes the drinking water standards in New Zealand, needs to consider whether some subsidy is required for smaller communities to assist them with getting appropriate drinking water."

Hawke's Bay water scientist Dexter McGhie says chlorination has short term advantages.

"But in the long term, there are other associated problems….the trouble with chlorination is organic matter in the water, when chlorine reacts with that it generates nasty chemicals which themselves can be toxic too," he says.

Havelock North residents are set to have their water chlorinated for at least another three months – even once the boil water notice is lifted later this week.