It found that several parties with responsibility for Havelock North's water supply, particularly the Hastings District Council, Drinking Water Assessors (DWAs), and the Hawke's Bay Regional Council failed to adhere to the high levels of care and diligence needed to protect public health, but said these agencies did not directly cause the outbreak.
Last week the inquiry resumed to consider any necessary changes to prevent or minimise similar incidents in the future, and will come back with its findings in December this year.
In the meantime, the Hastings District Council, Hawke's Bay Regional Council and Hawke's Bay DHB have taken steps to improve their practices and agreed that the situation today was very different to this time last year.
"There's a greater level of scrutiny on drinking water generally, and the effect of activities on drinking water," says HBRC chief executive James Palmer.
"We're more aware and have more knowledge of the risks and vulnerabilities, and state of the resource."
He said the likelihood of a similar event happening again had decreased due to all the agencies involved being more attuned to the risks, more proactive with risk management and able to manage events more quickly when they arise.
At the time of the outbreak, there was criticism of the authorities' response, particularly the Hastings District Council, but its chief executive Ross McLeod said the inquiry had found that it was generally effective overall.
"We do not think we have could have been any faster putting chlorine in - that happened almost immediately
"If we had had residual chlorine across the network last year, it's highly likely no-one would have got sick."
Ross says the council now had additional resourcing, had overhauled its inspection and maintenance regime, had improved its internal communications, and had taken expert advice on its water safety plan and procedures.
"We have a far greater focus on water safety - the community should be able to rely on the water supplier complying with the standards and water should be safe to drink."
The council's understanding of the aquifer as a water resource for Hastings Havelock North and Napier had grown since last year's events, James says.
"We are learning that rather than being a great underground lake to draw down from it's a system of underwater rivers.
"The water moves through the aquifers much faster than we previously realised, which means contaminants can move through the system more quickly than we had assumed."
In a submission to the inquiry last week, it said it now took a more active role in monitoring and supporting DWAs, and had clarified and defined the roles and responsibilities of key individuals within the DHB involved in responding to a major transgression event.
Regular operational meetings were being held with water suppliers and it planned to implement quarterly compliance meetings with water suppliers as well as create a means to report historical transgression information for individual water supplies.
