Cllr Mike Crowe is unhappy with the manner in which An Taisce compiled a report on wastewater treatment in Galway.
The issue was debated during Monday's Galway City Council meeting and Cllr Crowe remains adamant An Taisce should have contacted the council and Irish Water.
"I just wish to say that I believe it would have been proper and forthright if An Taisce had contacted Galway City Council and Irish Water for comment pre the report," Cllr Crowe said.
"They have been referred to as a statutory body, it is my view that they should start behaving as one. Ultimately Galway City Council and Irish Water have responsibility for water - the treatment of water, the quality of water in Galway city.
"To bring out a report like this - despite whether it is true or untrue - without actually contacting the relevant statutory bodies around water, Galway City Council and Irish Water, is a blatant, unforgiving exercise."
Cllr Crowe believes An Taisce did not use 'fair procedures' compiling the report.
"An Taisce are well able to understand the world we all live in, they understand when they wish to take part in a procedure, that fair procedure should be used," Cllr Crowe added.
"The truth here is in my view An Taisce didn't use fair procedures, blatantly and publicly accused the local authority - and by association the elected members - of not being capable or able to manage water in the city. I appreciate Brian Barrett (Galway City Council director of services ) and his units responses to this, it is clear."
Galway city residents have benefited from an improved water service in the last decade according to Cllr Crowe.
"I know first hand in my own area the level of work that has been done regarding water, replacing the pipes, all of that," Cllr Crowe continued. "It has been carried out by city council.
"I was on the last council when there was a significant amount of work carried out in and around the Mervue area with regard to the lead pipes.
"So for the last 10 years there has been more improvement, I believe, in water, and more importantly the delivery of water to the residents in this city than there has been for the previous 50 or 60 years.
"I will say publicly to An Taisce if you wish to be considered adults in the room then starting acting like it. The next time you go to produce a report around this, at least have the courtesy to contact the relevant bodies to get comment from them."