Ruapehu's Horizons Regional Council candidate John Chapman wants the Makotuku River to be made a target catchment under Horizon's One Plan.
He said the health of the river has been a concern to both the residents of Raetihi, who take drinking water from it, and to Ruapehu District Council.
Mr Chapman said thousands of dollars had been spent on water treatment in the area but the best solution was to have clean water in the first place.
"Until our river becomes a target catchment with proper nutrient management schemes in place to mitigate the effects of agriculture, the health of our rivers will remain challenged," he said.
"Horizons needs to list the Makotuku in the One Plan to enable that to happen."
Mr Chapman had wanted to speak to councillors at Wednesday's Environment Committee meeting but was declined but was able to address councillors via email.
But Ruapehu's incumbent regional councillor Bruce Rollinson said that was a "sledgehammer" approach.
Mr Rollinson said when the One Plan was drawn up it was deemed the level of farming in the catchment was sustainable.
Making it a priority catchment would require a plan change, he said.
"To get a plan change, that's essentially and whole new re-litigation of the One Plan."
Mr Rollinson said instead the catchment should be focused on in terms of monitoring it more closely and increasing environmental grants to the area.
"(Farmers) don't react well to regulation, they react well to community initiatives."