We drink tap water thinking it is safe, in fact we trust the laws that regulate its quality. But there is something flowing in our aquifers that is very little talked about. They are called nitrates, and their presence in Italian drinking water, especially in some areas, seems to be quite worrying.
Where do nitrates come from? First let’s understand what they are. Nitrates are highly soluble nitrogen compounds that, at low concentrations, are harmless. But when they accumulate in drinking water they become a serious health problem, so much so that they have been associated with an increased risk of colorectal cancer.
Their origin is closely linked to intensive farming, as Greenpeace reminds us. In Italy, over 660 million animals are raised in intensive systems where an enormous quantity of excrement is produced which, when it exceeds the absorption capacity of the soil, ends up straight into the aquifers.
Added to this is the massive use of synthetic fertilizers, which are also rich in nitrogen which turns into nitrate on contact with the air. According to estimates, 80% of nitrogen discharges into European Union waters come from intensive agriculture.
The situation in Italy
ISPRA 2025 data indicate that, out of a network of over 4,500 groundwater monitoring stations, 11.7% are outside the threshold, with average concentrations above 50 mg/L. A further 4.9% is in the warning range (40-49.99 mg/L). It is precisely these underground reserves that provide most of Italy’s drinking water.
The regions most affected by the problem are Lombardy, Veneto, Emilia-Romagna and Piedmont, not surprisingly the areas with the highest concentration of intensive farming. So much so that since 2018 Italy has been under European infringement proceedings for violation of the Nitrates Directive.
Does the legal limit really protect us?
The European Union sets the limit for nitrates in drinking water at 50 mg/L. That sounds reassuring, but there’s a problem: that threshold was established in 1998, based on research from the 1970s and 1980s. Since then, science has moved forward. A 2018 study of 2.7 million people over thirty years found an increased risk of colorectal cancer as low as 3.87 mg/L, less than a tenth of the current limit.
Danish research from 2024 confirmed the link between nitrates and intestinal cancers, estimating an annual cost for Denmark of over 270 million euros. And in 2025, a study based on 27 years of health data showed higher rates of colon cancer in people who drank water with concentrations above 9 mg/L.
The solution starts from the farms
To solve the problem we need to go to the source: downsize intensive farming, improve the disposal of animal waste, limit synthetic fertilizers and encourage more plant-based diets. Measures already translated into a bill, “Beyond intensive farming“, deposited in Parliament in March 2024 by Greenpeace. A proposal that is still waiting to be discussed.
The data is there, the solutions too. What is missing is the urgency of those who should act.
