A surprise formal investigation into whether Hastings District Council breached consents for Havelock North water supply bores was announced yesterday by Hawke's Bay Regional Council, which accuses it of withholding a GNS report.
On Tuesday, Hastings chief executive Ross McLeod said the councils were working "hand-in-glove" to find the cause of a campylobacter outbreak affecting a third of Havelock North residents - more than 4700 people.
However, after the investigation announcement yesterday he said he hoped the regional council would apply "the same rigour" to other possible causes of bacteria entering the aquifer.
He welcomed the investigation and said the regional council was "doing its job".
It will focus on whether the two Brookvale Rd bores supplying Havelock North were properly cased and sealed to prevent cross-aquifer and groundwater contamination.
The regional council asked Hastings council to produce all documents, names of people and emails relating to the bores since 1991 and for its timeframe for shutting down the Brookvale Rd bores as HDC switches to Hastings water.
It also asked for a GNS Science Water Dating Lab report of drinking water samples collected in May. The regional council claims this was withheld and that "other information" supported possible bore breaches.
Hastings Mayor Lawrence Yule said he learned of the GNS report from the regional council's press release announcing the investigation.
The GNS report showed three Hastings drinking water bores, Brookvale No 1, Wilson Rd and Portsmouth Rd, contained water less than one year old. All other council wells were secure because the water was older than one year.
The report, emailed on August 18, said GNS decided to send early results in light of the outbreak. Three-and-a-half weeks were needed for a final report with "full accuracy".
Yule said it was interesting the GNS report said Brookvale No 2 was secure, yet it recently tested positive for E.coli "which is part of this mystery".
The report arrived unexpectedly early and he did not know when it was read.
"The officer involved has been in the middle of transferring water, scene investigations and other work and I don't think he has given it any priority," he said.
"He would have given it priority if he knew. He is swamped with work - he is integral to the ... making-safe of the Hastings and Havelock North water supplies. He is out in the field working 20 hours a day.
"We have been completely transparent with the information. If somebody had wanted it earlier or asked for it we would have given it."
Yule said he was disappointed at the lack of dialogue before the investigation announcement.
The Regional Council investigation comes ahead of a comprehensive government investigation into the outbreak.
Test results yesterday for Hastings District Council water showed all was safe to drink but Havelock North residents were advised to first boil it.