The capital serves over 9 million people through Thames Water, one of the UK's largest water suppliers.
According to TapWater.uk's analysis, London scores 8.3/10 for drinking water quality in 2026. Water is supplied by Thames Water and has been tested for 23 contaminants across 58 postcode districts.
Average score
8.3/10
UK avg: 9.0/10
Areas tested
58
Issues flagged
79
PFAS detected
None
Yes, London tap water is safe to drink. Based on 58 areas tested, London has an average water quality score of 8.3/10 (below the UK average of 9.0/10). 79 contaminants were flagged above recommended levels across all areas. Water is supplied by Thames Water. The capital serves over 9 million people through Thames Water, one of the UK's largest water suppliers.
Contaminants flagged most often across the city.
All postcode districts in London, ranked by water quality score.
Learn more about the water quality issues relevant to this area.
Yes, London tap water is generally safe to drink. Across 58 areas tested, the average water quality score is 8.3/10. The capital serves over 9 million people through Thames Water, one of the UK's largest water suppliers.
Yes, you can drink tap water in London. It is regulated to UK drinking water standards, and across 58 tested areas the average water quality score is 8.3/10. Enter your postcode for the readings in your exact area.
The most commonly flagged contaminants across London are Nitrite (flagged in 57 areas), Coliform Bacteria (flagged in 15 areas), E. coli (flagged in 4 areas), Lead (flagged in 2 areas). No PFAS were detected.
Water in London has an average hardness of 274 mg/L CaCO₃, which is classified as very hard. Hard water causes limescale buildup in kettles and appliances. A water softener or filter may help.
The areas with the best water quality in London are N2 (8.8/10), N12 (8.6/10), NW11 (8.6/10).
Water in London is supplied by Thames Water. The capital serves over 9 million people through Thames Water, one of the UK's largest water suppliers.
No PFAS (forever chemicals) have been detected in any of the 58 areas tested in London.
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<script src="https://www.tapwater.uk/widget.js" async></script>Get a detailed water quality report for your exact area in London.