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tapwater.uk

London vs Cardiff

Water quality comparison

According to TapWater.uk, London scores 8.3/10 and Cardiff scores 9.5/10 for drinking water quality. Cardiff has the better water.

Cardiff has better water quality by 1.2 points


Key differences

Safety score

Cardiff scores 1.2 points higher than London.

Contaminants flagged

London has 113 issues flagged vs 0 in Cardiff.

Water supplier

London is supplied by Thames Water, while Cardiff uses Dŵr Cymru Welsh Water.


Top concerns by city

London

Nitrite64 areas
Coliform Bacteria19 areas
Iron7 areas
Turbidity7 areas

Cardiff

No contaminants flagged


Full city reports


Check your postcode

Get a detailed water quality report for your exact area.


More comparisons

Based on water quality data from 90 postcode districts across London and Cardiff. See our methodology for how scores are calculated.