UK Legal Limit
50 mg/L
WHO Guideline
50 mg/L
EU Standard
50 mg/L
Primary Sources
Agricultural runoff
Nitrate in UK drinking water is regulated at 50 mg/L. The WHO guideline is 50 mg/L and the EU standard is 50 mg/L. Enter your postcode on TapWater.uk to check Nitrate levels in your area.
High nitrate levels in drinking water are most concerning for babies under three months old, where the conversion of nitrate to nitrite in the gut can interfere with the blood's ability to carry oxygen — a condition known as methaemoglobinaemia. In adults, some research has suggested a possible link between high nitrate intake and cancer risk, though the evidence is still being assessed.
The main source of nitrate in UK drinking water is farming — specifically the use of nitrogen-based fertilisers and the spreading of animal manure on fields. Nitrate leaches through soil into groundwater and rivers, which are often used as drinking water sources. Sewage and urban runoff also contribute, though usually to a lesser degree.
| Jurisdiction | Limit / Guideline | Notes |
|---|---|---|
| UK (DWI) | 50 mg/L | Regulated under the Water Supply (Water Quality) Regulations 2016 |
| WHO | 50 mg/L | World Health Organization Guidelines for Drinking-water Quality |
| EU | 50 mg/L | EU Drinking Water Directive (2020/2184). The UK no longer automatically mirrors EU standards post-Brexit. |
Reverse osmosis
A membrane filtration process that removes up to 99% of contaminants by forcing water through a semi-permeable membrane under pressure. Highly effective but produces some wastewater.
Ion exchange
Replaces unwanted ions (such as nitrate or lead) with harmless ones using resin beads. Effective and widely used in both whole-house and point-of-use systems.
Distillation
Water is boiled and the steam condensed, leaving most contaminants behind. Highly effective but slow and energy-intensive — typically used in countertop units.
These list nitrate among what they reduce. Check your own report first — a filter is only worth buying for a contaminant your supply actually has.
Listed to reduce Nitrate
Waterdrop G3P600 Reverse Osmosis
Reverse Osmosis · NSF/ANSI 58, NSF/ANSI 372
Typical price
£550approx.
Affiliate link: we may earn a commission at no extra cost to you.
Listed to reduce Nitrate
Osmio PRO-III Ultimate Whole House
Whole House · NSF/ANSI 42, NSF/ANSI 61, WaterMark
Typical price
£499approx.
Affiliate link: we may earn a commission at no extra cost to you.
Want to know the Nitrate levels in your water? Enter your postcode to get a free report for your area.