The failings applied especially to its mid-level managers, Mr Stevens said, who delegated tasks but did not adequately supervise and ensure their implementation.
He also noted the district council did not maintain the bores adequately, and was slow to get a report on bore head security.
Yesterday the council said they accepted the Inquiry's findings, and assured the public they would be remedying any shortfalls to ensure such an incident never occurred again.
Yesterday Hastings mayor Lawrence Yule said while the contamination's cause was not directly linked to their council, he had "huge regret" for the part they played in the outbreak.
"I'm the leader of this council, our community expect to have safe drinking water so I've undertaken a tremendous amount of personal responsibility to get us through this crisis ... but I didn't personally cause this contamination," he said.
Addressing the criticisms raised in the report, Mr Yule said council had improved its response plan, but that there should have been more information shared about the 1998 incident.
"It was disappointing to find out during this investigation that some of those recommendations from 1998 were not carried out, but we don't believe they were actually linked to what happened here," he said.
Council chief executive Ross McLeod said the council would be taking numerous actions to ensure drinking water safety - which included a "complete overhaul" of risk management and compliance systems, and review of their water operations.
When asked if any staff could lose their jobs, he said he would not comment on any potential action taken against staff, as "those sorts of matters will be dealt with when the review team comes back".
"I'm not ruling anything in or out," he said. "I think you can rest assured that we are very focused on making sure nothing like this can happen again, we will examine very carefully the deficiencies that have been highlighted".
He had no intention to resign, as the council had expressed an expectation he would fix any deficiencies.
"We are very focused on making sure that this can't happen again and that there is accountability in place both ongoing and for what's occurred."
Yesterday Mr Yule said he did not know whether yesterday's events would hurt his chances as the National Party candidate for Tukituki.
He would do what he could to remedy the situation while still mayor, but "ultimately voters will decide what is my level of accountability or responsibility for this, and I'll leave that to them".