Christine Rose: Greenpeace campaigner on the concerning levels of nitrate in Ashburton water - Heather du Plessis-Allan Drive

There are concerns about Ashburton's high nitrate levels.

Greenpeace undertook free water testing in the region over the weekend and 77 percent of samples had more than one milligram per litre of nitrate.

Up to 11 percent exceeded the current nitrate standard of 11.3 milligrams per litre, including one at 25.7 milligrams.

Lead campaigner Christine Rose says there’s severe nitrate contamination in the region.

"There's clear evidence that it's from big dairy, too many cows and too much synthetic nitrogen fertiliser."

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