Environment Canterbury councillors are set to vote on a proposal to declare the region's controversial nitrate emergency over.

This time last year the council voted to declare an emergency as nitrate levels climbed across the region, with council and private water supplies seeing levels inch towards - and in some cases breach - the national drinking water standard of 11.3 milligrams of nitrate per litre of water.

The notice of motion, set to be decided on Wednesday and proposed by former councillor Vicki Southworth, included the declaration of emergency, a recognition the council should "take a leadership role" to urgently address the issue of groundwater pollution, and requested staff provided workshops for the incoming council on the scale, causes, and impact of nitrate pollution.

It also sought advice on the costs for private bore users and councils to treat nitrate pollution or find alternative sources, as well as options to reallocate costs so "nitrate polluters contributed to the costs of nitrate removal from drinking water".

At the time, Agriculture Minister Todd McClay called the declaration "gimmicky", while Federated Farmers deemed it unhelpful and politically motivated.

In a report to be presented to the council on Wednesday, staff recommended councillors vote to recognise the work that had been done so far responding to the notice of motion, and agree not to have staff carry out the investigation into how to pay for nitrate contamination treatment.

Further, staff suggest the council's Drinking Water Action Plan provided "sufficient response" to the notice of motion, delivering on the council's statutory responsibilities, and that the notice of motion could now be resolved.

A regional council spokesperson described the Drinking Water Action Plan as "a collation of various workstreams" which "captures the work we are doing in the drinking water space".

Greenpeace programme director Niamh O'Flynn criticised the council's reliance on the Drinking Water Action Plan, which she said "did not sufficiently address the fact that rural Cantabrians cannot guarantee the safety of the water coming out of the taps".

She said it was deeply concerning the council was proposing resolving the notice of motion.

"A few discussions by the council didn't magically make the problem of nitrate pollution coming out of people's taps and polluting our rivers go away, and I think ECan [Environment Canterbury] have a bare minimum responsibility to keep telling the truth about the situation in Canterbury, which is that there is indeed a nitrate emergency."

O'Flynn noted the regional council had consented tens of thousands of extra cows for the region this year alone.

"Where does it stop and how can we say a nitrate emergency has been solved when it's very clearly going to get worse from here?"

Figures obtained by the Green Party under the Official Information Act showed the regional council had granted consents for an extra 57,000 cows in 2026.

Between 1990 and 2022, Canterbury's dairy herd increased by more than 1000 percent, to well over a million cows.

The staff report found treatment systems to remove nitrate from drinking water cost between $3000 to $5000 for a whole-house system, plus annual maintenance costs.

The report said surveys found a lack of awareness among private bore users and of a need for them to "understand" their source water and to test and treat, and that cost was less of an issue than raising awareness.

It was "ridiculous" to place that responsibility on individual bore owners O'Flynn said.

"If you have no control over the amount of pollution that's going into your bore, how can you bear the responsibility for dealing with the problem at the other side?

"We live in a country where most people think everyone should have clean drinking water coming out of their taps. Environment Canterbury are responsible for protecting source water, from preventing pollution getting into source water in the first place."

But in any case "awareness doesn't magic pollution away".

"Awareness doesn't stop the industry in your region polluting your drinking water, and awareness certainly doesn't put an extra couple of grand in your bank account so that you can keep your family's drinking water safe."

Federated Farmers president Colin Hurst said the group welcomed the proposal to dismiss the notice of motion, calling it a "cheap political stunt".

But he said it was important to understand in more detail what was causing the problem.

"Sure, farming is part of the issue. It's also some of the irrigation practices have been changing ... There's a number of reasons causing this.

"The key thing is we need to understand the trends. Is it getting worse? Is it getting better or is it staying the same? So I'm not quite sure if we understand that completely yet."

Hurst said farmers were a lot more attuned to understanding nitrate issues and making reductions in nitrogen, as well as other practices such as fencing off waterways.

"It's not exactly an easy topic to understand, but certainly there's no question too much nitrogen is not good for the environment," Hurst said.

Forest and Bird regional conversation manager Nicky Snoyink said the proposal to declare the nitrate emergency notice of motion resolved was very premature.

"There's nothing to show that anything is actually improving.

"It's all very well to have a drinking water action plan but that's all it is ... there's no actual data to show that anything is improving so you know they haven't addressed the elephant in the room which is dealing with the pollution limits in the plan that will actually achieve the desired freshwater outcomes and clean up our drinking water."

Snoyink said the declaration should not be altered until studies showed decreasing nitrate levels.

"The numbers don't lie. We need the actual evidence to show that things are changing before they remove the nitrate emergency.

"We not only have more and more dairy cows being consented to go out onto the Canterbury Plains ... we not only have no evidence that things are getting better, we also have more dairy cows being consented."

The costs of treating nitrate pollution needed to lie "where the pollution is coming from, which is largely the dairy industry in Canterbury", Snoyink said.

Environment Canterbury's most recent groundwater report showed 59 percent of monitored sites had worsening levels of nitrate in 2024, and 10 percent had breached the drinking water standard.

The 2025 groundwater report was not expected to be released until next month.

In the largest study of its kind, released last year, GNS Science confirmed Canterbury had the highest percentage of elevated groundwater nitrates in the country, following testing of 3800 rural drinking water samples from private wells between 2022 and 2024.

Researchers identified nitrate-rich cow urine as a primary cause of contaminated groundwater.

The study found more than 21,200 people nationwide could be drinking water contaminated with nitrate above the legal limit while more than 100,000 people could be drinking water above half the legal limit - one in three rural homes.

New Zealand's nitrate limit of 11.3 milligrams per litre is based on 1958 World Health Organization guidelines specifically for preventing infant death from methaemoglobinaemia or blue baby syndrome.

Emerging research has pointed to health risks at far lower levels.

In 2021, the College of Midwives advised members to tell women on private bores to get their water tested, and for pregnant and breastfeeding mothers to switch to bottled water if nitrate levels were over 5mg/L.

A 2021 analysis by Victoria and Otago universities found a potential link with bowel cancer at levels as low as 0.87mg/L.

A 2026 study of more than 750,000 New Zealand births found higher nitrate concentrations in drinking water were associated with small but consistent increased risks of pre-term births at levels well below the current legal limit.

The study also found the risk of pre-term birth increased by about 1 percent for each milligram a litre (mg/L) of increased nitrate levels, and comparing births from areas where nitrate levels were very low (close to zero) to those with the highest levels in the study (over 5mg/L) showed a starker jump - around an 8 percent increase in pre-term births.

In June RNZ revealed the Ministry of Health had quietly launched a review into the health effects of nitrate in drinking water.

The outcome was expected to be public by the end of the year.

Earlier this month, regional councillors heard from water regulator Taumata Arowai, which suggested there may need to be a long term nitrate limit to accompany the current short term acute limit.

Science advisor Jim Graham told the council the agency was considering a new long-term value in response to increasing scientific evidence of long-term health effects at levels far lower than the current limit.