"I think the issue that's been identified is that our staff and their staff were looking at this [water issue] through a different lens," he said,
Hawke's Bay Regional Council chairman Rex Graham said the relationship between the councils' staff "needs to improve".
"There has been historically a lot of tension amongst the staff," he said. "We've made some changes and ... I'm looking forward to that improving during my tenure as chair".
When asked, Mr Graham said he had never been made aware of this issue from council management, but that he had always observed it.
There would always be a "natural tension" when one council was charged with a regulatory function - as HBRC was under the RMA - and had to check on the activities of another council.
However, he said more needed to be done to improve staff relations, "you can be a regulator and still get on with the people you're regulating".
"[Both councils] are very conscious of it, and we're both are trying to work hard to look at ways to improve it."
Details were scant when both councils were asked about their take on the tense relationship being at staff level, and what was being done to remedy this.
A Hastings District Council spokesperson said they accepted the inquiry's findings about the working relationships between the two councils around water, and the consequences of this.
"The quality of relationship at officer level varied from time to time and given this, there was no obvious recognition that the relationship was dysfunctional or in a poor state," they said. "There was no formal reporting to councils".
Council staff, led by chief executive Ross McLeod, were committed to putting in place effective working relationships on water safety.
A Hawke's Bay Regional Council spokeswoman reiterated that their regulatory function obligation under the RMA could lead "to a difficult position when HBRC is required to regulate other councils".
Both representatives spoke of their involvement in the new joint working group involving the two councils, the Hawke's Bay District Health Board and the Drinking Water Assessment Unit.
The HBRC spokeswoman said they continued to be committed "to working with all the councils and agencies to ensure any required changes are made to ensure this doesn't happen again."
The lack of liaison between both councils were highlighted in the 230 page inquiry report, which recorded "above a significant level of ill-feeling and tension in the relationship between the two councils".
It was noted that while HBRC was "information heavy" on general aquifer and catchment matters, they lacked knowledge on HDC's infrastructure and water take operations.
"The inquiry finds that a substantial and effective level of liaison between the regional council and the district council was therefore necessary, but that the regional council failed to initiate this".