Former councillor Darryl Johnson, who has performed many good deeds for Port Pirie, has been found to have committed misconduct in public office.
The finding was made by SA Ombudsman Wayne Lines in a report tabled at the latest Port Pirie Regional Council meeting.
The Ombudsman made no recommendations on action against Mr Johnson because he is no longer a councillor.
The matter relates to a move by council on waste disposal fees on October 25, 2017.
The council decided that the fees would revert to the original 2017-18 schedule.
The Ombudsman looked at whether the then councillor had breached conflict of interest provisions at the meeting because of his involvement with his father who ran a building company and used the tip.
He said Mr Johnson's father, builder Malcolm Johnson, had objected in The Recorder to council's interpretation of its fees.
The council administration had changed its interpretation of the schedule of fees to distinguish between domestic and commercial users with the latter paying a minimum $65.
Malcolm Johnson was quoted in the newspaper as saying the changes to the fees were hurting local business and were possibly outside the Local Government Act.
"I consider that Malcolm Johnson, as a commercial user of the waste transfer station, would gain a benefit or suffer a loss, depending on the outcome of the move," the Ombudsman said.
He said Darryl Johnson had said he was unaware of his father's campaign, but he (the Ombudsman) had some difficulty accepting that.
Darryl Johnson had been employed by his father's company.
"Malcolm Johnson's interest in the move does not arise due to his personal interest in the matter and public campaign against the change to the fees," he said.
"His interest arises due to the fact that he would receive a pecuniary benefit or suffer a pecuniary loss, depending on the outcome of the consideration of the move.
"I consider Darryl Johnson had a material conflict of interest relating to the move.
"The Local Government Act provides that a member must tell the meeting of any material conflict of interest and must leave the chamber.
"He did not declare a material conflict and did not leave the chamber. He breached the Code of Conduct."
The Ombudsman had a referral from the Independent Commissioner Against Corruption to investigate the matter.
Mr Lines also found that Darryl Johnson did not breach the Local Government Act and Code of Conduct relating to three other council resolutions.
The report attracted little comment at the latest meeting other than for Cr Neville Wilson to say that "we have no great concerns about what went on".
During his time on council, Darryl Johnson pioneered projects including murals along the Solomontown overpass, the illumination of the Main Street palms and the creation of highway signs pointing to Port Pirie.
He played a key role in the development of the sport hub.
I consider Darryl Johnson had a material conflict of interest relating to the move ... he did not leave the chamber.Wayne Lines, Ombudsman
The council has featured in several reports by the Ombudsman.