The Havelock North gastro outbreak - and whether the same catastrophe could unfold in other places - is the hot topic at a major water conference this week.

The E.coli contamination of the Hawke's Bay town's water supply in August, causing about 5200 people to become ill, prompted a Government inquiry that kicks off with a public hearing in Hastings next Thursday.

Water New Zealand chief executive John Pfahlert told the Herald the debacle would be front and centre of his organisation's annual conference, running over the next three days in Rotorua.

Sessions at the conference would discuss the outbreak, including an industry expert panel discussion planned for Friday.


Although reluctant to speculate on what caused the contamination while multiple investigations were still taking place, Pfahlert said it had raised major questions for the water sector that stretched well beyond Havelock North.

"I think what it raises for the sector is an opportunity to have a look at the wider regulatory environment around how we control drinking water standards in New Zealand.

"What we are hoping will come out of the inquiry is an opportunity to run the ruler over the legislation, the way in which it is administered by the Ministry of Health through drinking water assessors at district health boards, and perhaps some of the engineering issues."

These included how water wells were drilled and how they were made secure.

"Another issue is whether we've got an appropriate and adequate training regime for people who work in water treatment plants."

He hoped the Government inquiry would take a two-stage approach looking at the Havelock North episode along with the systemic issues it raised for the wider sector.

"There's a whole host of councils around the country that have started to look at their bore security and the way they manage their water safety plans - there has been a flurry of activity."

Asked how pressing he thought the issue was, Pfahlert said: "I think it gets urgent to the extent that we need to do something, but I don't think it makes a substantial difference whether we do it tomorrow, or in 12 months."


In general, New Zealand's network provided clean drinking water for people the vast majority of the time, he said.

"This incident simply points out that if you are supplying your community with untreated water - even if it's from a secure source - you run the risk that when something goes wrong, you can actually make a lot of people very sick."

The often controversial topics of water chlorination and fluoridation were also being thrashed out at the conference, with one keynote speech drawing on a new report showing that every dollar spent on fluoridation was equivalent to $9 in public health benefits.

"We approach these things from a fairly straight up-and-down scientific basis, but we acknowledge also that there are people out there who simply have a philosophical opposition to putting chemicals in water, whether it's fluoride to improve dental care, chlorine to kill bugs to stop people getting sick, or aluminium compounds to take sediment out of the water."

About half of New Zealand's population has fluoridated drinking water.

"The evidence is all pointing towards the fact that in low-decile communities - particularly those dominated by Maori and Pasifika people, where they've got un-fluoridated supplies - there are very significant economic benefits, not just health benefits.


"We try to sell it on that basis, but it's been a long-term game and we've got groups that are continually taking district councils to court. And that's just the business, that's just the way it is."

Just as fluoride had been a charged issue over recent years, Pfahlert expected that chlorination would increasingly become a debated topic.

"I think more communities are going to be faced with conversations with their local district council about whether drinking water supplies should be chlorinated or not, and in communities where they've had a long history of fresh water from a pure, clean aquifer with no problems, that's going to be a pretty hard sell.

"Because there's no doubt that you'd end up with different odour and taste issues associated with chlorinating water supplies - and of course a small cabal of people opposed philosophically to adding chemicals.

"I suspect that if you went to the Havelock North community and ran a poll and asked them, would you like your water supply to be treated permanently with chlorine, they'd probably say no - and there's the irony."