Cr Cull was among councillors at Tuesday's infrastructure services committee meeting, but retired from the meeting when debate turned to the issue of illegal water connections.
Yesterday, Cr Cull confirmed his decision to withdraw came after a complaint - "possibly" from another councillor, whom he would not name - over a conflict of interest.
In April, Cr Cull admitted he was one of 52 property owners with illegal or informal water connections, having not paid water rates since purchasing his Portobello home 15 years ago.
He said he had notified staff two years ago, but was yet to have the situation resolved.
He remained at the council table when the issue was debated by councillors in April, to suggest how the council should respond to the wider problem, before making his admission.
Yesterday, Cr Cull told the Otago Daily Times he had been queried about a possible conflict during the April meeting, but did not withdraw because he felt some issues were not addressed in a staff report to the April meeting.
He also felt he could not have a conflict of interest if he stood only to lose money by being required to pay water rates.
That led to the complaint over his conflict of interest, and "having taken a bit of advice I agree I could have [a conflict] this time".
"I wasn't going to make the same mistake," he said.
