In a landmark legal decision, the High Court has confirmed that Environment Canterbury (ECan) made a legal error when it permitted nitrate pollution from farming across much of the region without the safeguards required under the Resource Management Act.
The judgment, delivered on 22 December 2025 by Justice Mander, found that ECan’s Rule 5.63 in the Canterbury Land and Water Regional Plan – which treated farming-related nitrate discharges as a permitted activity – was introduced without properly applying section 70 of the Act. That section requires councils to be satisfied that such discharges would not cause “significant adverse effects on aquatic life” before allowing them without a consent.
The Court said the rule was adopted without adequate evidence to show it would protect freshwater ecosystems, even as nitrate levels in waterways and groundwater across Canterbury continued to rise.
Dr Matt Hall, Director of Research and Legal at the Environmental Law Initiative, which brought the challenge to the Court, says the decision highlights how the rule failed to safeguard freshwater – including places people drink from, swim in and depend on for mahinga kai – and “goes to the heart of Canterbury’s current nitrate crisis.”
Despite the Court’s finding of error, the rule remains in force because the High Court held that legal challenges to regional plans must generally be raised within strict time limits, and more than a decade has passed since the plan became operative.
Earlier this year, Environment Canterbury declared a nitrate emergency, revealing that more than 60 percent of monitored wells in the region show rising nitrate contamination, a concern for drinking water health and freshwater life.
The judgment also comes amid controversial changes to national freshwater protections. In August 2025, Parliament amended the Resource Management Act to allow councils to permit certain discharges even where waterways are already degraded – so long as the conditions aim to reduce pollution over a period of up to 10 years. Critics say this weakens critical bottom lines for water quality.
Dr Hall and environmental advocates argue the Court’s finding reinforces the need for stronger, evidence-based protections for freshwater, rather than permissive rules that allow ongoing pollution. They say this is especially urgent for communities, iwi and hapū in Canterbury and beyond who rely on clean water for health, cultural practices, and the environment.
As the debate continues over how to balance agriculture, environmental protection, and tangata whenua interests in freshwater management, the ruling marks a significant moment in the ongoing fight for healthy rivers, streams, aquifers and coastal ecosystems in Aotearoa.
