The major part of the Havelock North Water Inquiry starts today with evidence and submissions from more than 20 people over the next fortnight.
The inquiry, at the Hastings courthouse, chaired by retired Court of Appeal Judge Lyn Stevens QC sitting with former Director-General of Health Dr Karen Poutasi and Wellington city engineer Anthony Wilson, was ordered after E. coli contamination which led to an outbreak of gastroenteritis among more than 5000 people in August.
Preliminary sittings took place in October and Stage 2 was to have started at the end of November but was adjourned because of a since-dropped Hawke's Bay Regional Council move to prosecute the Hastings District Council.
It is looking at how the Havelock North water supply system became contaminated, how the problem was addressed, how local and central government agencies responded to the public health outbreak that occurred as a result of the contamination, and how to reduce the risk of similar outbreaks recurring, including possible recommendations on change.
It is to report to Government by the end of March.
Known as the substantive hearing, this week's proceedings will focus on the source of the contamination, prior knowledge, and faults or failures, and will include Tony Cussins, who produced the Tonkin and Taylor report which followed contamination of the supply in July 2013.
Brookvale Bore No 3 had since been shut down, but the report was only just emerging as the outbreak began almost six months ago.
Hearings next week will focus on facts surrounding the outbreak, adequacy of outbreak responses and adequacy of contingency planning.
Counsel assisting the inquiry will make submissions following the hearing of the listed witnesses and any person who is the subject of or is affected by matters raised in the submissions will have the opportunity to respond in writing.
Last week Hawke's Bay Today reported the costs of the crisis were stacking up as the Hastings District Council announced it spent nearly $900,000 in investigations and legal fees.
Details of the costs included those incurred by the Hawke's Bay Regional Council prosecution action as well as the Government inquiry and technical investigations.
Hastings District Council said the costs associated with the Hawke's Bay Regional Council prosecution action totalled $71,000 in legal costs and $200,000 in technical investigation costs.
Costs associated with identifying the cause of the contamination and assisting the Government inquiry totalled $133,000 in legal costs and $451,000 in technical investigation costs.
Hastings District Council chief executive Ross McLeod yesterday commented that the investigation costs were not solely attributable to the Government inquiry.
"We are a water supplier and our community has made it clear it wants us to find out how the contamination occurred and to make sure it can't happen again," he said.
"While this work will be crucial for the inquiry, we would have done much of it anyway."