Organisations urge WHO to review nitrate drinking water limit
An open letter signed by 85 organisations says the guideline has not kept pace with evidence on possible health risks. New Zealand’s drinking water limit matches the WHO benchmark.
Eighty-five organisations have asked the World Health Organization to include nitrate in a review of its drinking water guidelines, saying the current limit does not reflect recent evidence on health risks. RNZMedical Xpress
The WHO guideline is 11.3 milligrams per litre for nitrate-nitrogen, equivalent to New Zealand’s maximum acceptable value. The letter points to evidence linking long-term exposure to colorectal cancer and adverse birth outcomes. RNZMedical Xpress
A Ministry of Health review of nitrate’s health effects in drinking water is expected by the end of the year. In Canterbury, a 2025 survey found 38 of 358 sampled wells exceeded the drinking water limit. RNZ