New tests show there are worrying levels of nitrates in some of the tap water in parts of rural Canterbury.
Fish and Game blames intensive dairy farming, but Federated Farmers say the research is a beat up.
Strict pollution rules have been in place in Canterbury for several years. Fish and Game worked with researcher Dr Mike Joy and tested more than 114 samples – they say concerning levels were found in more than half.
"The city water supply, the municipal supply, is still looking good, but it’s those rural ones that are still getting high," says Dr Mike Joy.
Otago University Department of Health, Professor Michael Baker, says it’s a product of intensified farming in New Zealand, and the country’s love affair with putting lots of fertiliser in the environment.
And while levels were within the official healthy limit, Michael Baker says it’s still concerning.
"There’s more research coming out showing that levels of nitrate below our current drinking water standard are associated with an increased risk of cancer," he says.
The Canterbury District Health Board says the city’s water is safe but "medium and high nitrate levels do occur in shallow groundwater in rural areas around Canterbury".
It says “if people are concerned about their bore water quality they should get in contact with Environment Canterbury or Canterbury District Health Board’s Public Health Unit.”
Federated Farmers Chris Allen says the research is a "beat up" and dairy farmers say they are unfairly taking the blame for what are quite low nitrate levels.
"Whether we're growing lettuces, whether we're growing winter feed, whether we're growing sheep, actually even native forests even have nitrate coming out," he says.
Nitrate levels are expected to rise, with existing pollution still making its way through the groundwater system.