The crisis had Greenpeace firing thousands of emails to Hawke’s Bay regional councillors, pushing for the project to be shelved in light of the contamination.
But one councillor maintained opponents to the dam were drawing a long bow in trying to link it to the public health incident.
Peter Beaven said the Tukituki River was 2.5km from the Havelock North aquifer and scientists had said it was highly unlikely the river was the contamination source.
“It is more likely to be some form of localised contamination but they have had helicopters up and council staff looking for the source for over a week and they still have not found it.
“I think the only way Ruataniwha could put water quality at risk is if the entire area filled up with dairy production and that is unlikely.”
Irrigation New Zealand (INZ) chief executive Andrew Curtis said Greenpeace was out of order in sending the emails to councillors.
“The reasons why Havelock North’s drinking water is contaminated are yet to be determined. There is no evidence at all that irrigation or intensive agriculture have contributed.
“The area surrounding the water supply is dominated by vineyards, orchards, cropping and low-intensity livestock,” he said.
The contamination was more likely to have come from one of the surrounding bores being affected, possibly from an unprotected well head.
Better well head construction and protection were key focus areas for INZ and bore standards had been considerably improved in recent years.
“But there are a large number of old bores in that district and the newer bores are definitely at a higher standard.”
