Source: Greenpeace
Greenpeace is alarmed by Environment Canterbury’s lack of action on nitrate contamination, as new data reveals that 38% of Canterbury households on private water sources are in areas where groundwater nitrate contamination have exceeded levels associated with an increased risk of preterm birth.
Greenpeace Freshwater Campaigner Will Appelbe says the figures should be sobering for everyone in the region.
“Environment Canterbury has just confirmed that over a third of households on private self-supplied water are in areas with groundwater that could put pregnant people at risk. This is absolutely unacceptable.”
“When ECan declared a nitrate emergency in September last year, the understanding was that they would take a leadership role to urgently address the crisis.
“It’s nearly been a year and the question remains: when will ECan actually address the problem and confront the industry responsible for this pollution?”
“These high nitrate levels are the consequences of unchecked dairy expansion and intensification on the Canterbury plains, which is the main source of nitrate contamination. We simply have too many cows and too much synthetic nitrogen fertiliser being thrown on the land.”
The current legal limit for town supplies is 11.3 mg/L, which was set in the 1950s to protect against blue baby syndrome. But a growing body of scientific evidence has linked nitrate levels as low as 1 mg/L to an increased risk of bowel cancer, and levels above 5 mg/L has been linked to an increased risk of preterm birth.
There is increasing community concern about nitrate contamination in Canterbury, which led to Environment Canterbury declaring a Nitrate Emergency in September 2025. The declaration stated that the council:
- 1. Should take a leadership role to urgently address the issue of groundwater pollution impacting drinking water sources and supplies.
- 2. Requests that ECan staff bring a workshop to the next term of Council to outline the scale, causes, spatial distribution, latest lag time research, and current and predicted impacts of nitrate pollution in Canterbury.
- 3. Requests advice on the indicative cost to drinking water suppliers and private well owners, and consider options so that nitrate polluters contribute to the costs of nitrate removal.
- ECan’s briefing today was an update from staff on this work. Councillors heard there are an estimated 20,000+ domestic self-supplies in Canterbury, which are households who source their water from private bores or other sources – not town supplies.
Over 500 of those households are in areas where groundwater nitrate levels have previously exceeded 11.3 mg/L, and over 7,500 households are in areas that have exceeded 5.65 mg/L.
“There is mounting evidence that has linked nitrate contaminated drinking water with several human health risks, and these new figures today show how much Canterbury is at risk,” says Appelbe.
Just last week, a new study from researchers at Canterbury, Otago, and Massey universities revealed that nitrate contamination in drinking water could be responsible for up to 120 premature births a year in New Zealand, at levels much lower than New Zealand’s legal health limit. The New Zealand College of Midwives recommends pregnant people consider another source of drinking water, if their water supply exceeds 5 mg/L, because of the increased pregnancy risks.
At today’s meeting, council staff also presented the indicative costs to install filters in households that remove nitrate from drinking water, which were in the range of $3,000 to $5,000 for whole household systems, and $1,000 to $2,000 for systems under the sink.
However, staff have yet to present funding options that the council could implement to ensure that those responsible for nitrate pollution contribute to the costs of nitrate removal from drinking water – as required in the Nitrate Emergency Declaration.
Appelbe says it’s critical that Environment Canterbury continues its work under the declaration – the first of its kind in New Zealand.
“Right now, rural families in Canterbury can’t safely drink their water thanks to intensive dairying. The industry that’s polluted their water should be responsible for fixing the problem.
“Funding models that force polluters to pay for filtering are the bare minimum, and the Council must have those options on the table. But ultimately, we have to regulate the intensive dairy industry to stop the pollution at the source. That means fewer cows and phasing out synthetic nitrogen fertiliser.”