He was accompanied on the forest visit by council staff and 1080 opponents.
Later, while commenting in a Northland Age article about opposition to 1080 on social media, Finlayson said he believed ''a lot of people who are genuinely concerned about our environment and animals have had their emotions hijacked by the type of emotive propaganda that would make Goebbels proud''.
The complainants alleged that drinking the water was a health and safety risk, and that Finlayson's comments were inappropriate for a elected official and aimed at them personally.
The council appointed Auckland lawyer Paul Sills to investigate.
Sills said health and safety was beyond the scope of his report but, regarding the other complaints, he found Finlayson had breached the council's code of conduct in four areas.
The councillor's comments did not identify any individuals but Sills said they were dismissive of the views of 1080 opponents. And, safe or not, drinking the water was not sensible and risked damaging the council's reputation. Sills said the breaches were not extreme.
The biggest issue was that Finlayson ''had not stopped to think of the impacts his actions would have on his position as councillor and in turn on the reputation of the council. He, like the opponents of the use of 1080, have been caught up in the debate and in their own strongly held opinions of whether 1080 should be used or not."
Sills recommended that Finlayson be reminded of his obligation to separate his official duties from his personal opinions. The council could also request an apology to the complainants.
He did not call for Finlayson to step down from his pest control role, saying the council was better served making use of his expertise.
Nicolson dismissed the health and safety complaint, saying water tests within the catchment on September 29, a day after the 1080 drop, had tested negative for the toxin or in one case returned a result of 1 part per billion, below the limit for safe drinking water.
He also said Finlayson should be given credit for showing leadership and articulating his views despite the opposition of some members of the community.
Nicolson said one of the report's key findings was that the council did not have an official position on the use of 1080. That left Finlayson having to express his own views instead of the council's.
Nicolson said that was his fault and at today's meeting he would recommend councillors consider adopting a 1080 policy.
Finlayson said the report was biased because he was given no chance to respond to further information after his first meeting with the investigator.
It also failed to take into account the context of what had been happening on social media and that the complaints ''were part of a campaign to silence an elected official''.
Finlayson said drinking the water posed no health and safety risk because he had been briefed on the results of the water tests beforehand.
He had to contest misinformation about 1080 because losing the social licence to use the ''vital pest control tool'' could be disastrous for New Zealand's native fauna.
He conceded he had been frustrated at times during his exchanges on social media but did not believe he had been contemptuous, and said his comments were not directed at individuals.
