What it is
Nitrate is a naturally occurring form of nitrogen that plants need to grow. It dissolves very easily and travels with water through soil, so it is one of the most common findings in private supplies in farmed areas.
Where it comes from
Most nitrate in groundwater comes from agricultural land: fertiliser, manure and ploughed grassland. Septic tanks, soakaways and slurry stores close to a well or borehole are the other usual causes. Shallow wells and springs are more exposed than deep boreholes, and levels often rise after wet winters.
Why it matters
The main concern is for infants under about six months who are bottle-fed with water high in nitrate. In the body it can be converted to nitrite, which interferes with how blood carries oxygen (a condition sometimes called blue-baby syndrome). Pregnant women are also advised to keep intake low. For older children and adults the risk at the levels usually seen in UK supplies is low, but the guideline applies to everyone.
What can be done about it
Nitrate cannot be removed by boiling, which concentrates it, or by ordinary carbon filters. It is removed by ion-exchange nitrate-removal units or by reverse osmosis, either for the whole house or at the kitchen tap. A Pozzani engineer will also look at whether the source can be better protected, for example by sealing the wellhead or moving away from a soakaway.
Information last reviewed 5 October 2026 by Pozzani Pure Water.