Skip to main content
tapwater.uk

Cardiff vs London

Water quality comparison

According to TapWater.uk, Cardiff scores 9.5/10 and London scores 8.3/10 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

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


Top concerns by city

Cardiff

No contaminants flagged

London

Nitrite64 areas
Coliform Bacteria19 areas
Iron7 areas
Turbidity7 areas

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 Cardiff and London. See our methodology for how scores are calculated.