16 postcode districts testedWater quality in Wales

According to TapWater.uk's analysis, Wales scores 9.5/10 for drinking water quality in 2026, based on data from 16 postcode districts. Water quality across Cardiff, Swansea, Newport and rural Wales. Supplied by Dŵr Cymru Welsh Water.

9.5 / 10

16 areas tested · 1 supplier

Tap water in Wales has an average safety score of 9.5 out of 10 based on testing across 16 postcode districts. Water is supplied by Dŵr Cymru Welsh Water. The overall water quality is good. Data is sourced from the Environment Agency and water company testing via the Stream Water Data Portal.

Cities in Wales

Average water quality score by city.

Swansea7 areas tested9.6 out of 10 Cardiff9 areas tested9.5 out of 10

Areas to watch

CF24Cardiff9.3 out of 10 CF5Cardiff9.4 out of 10 CF3Cardiff9.4 out of 10 CF11Cardiff9.4 out of 10 CF14Cardiff9.4 out of 10

Cleanest water

CF30Cardiff10.0 out of 10 SA4Swansea9.6 out of 10 SA3Swansea9.6 out of 10 SA1Swansea9.6 out of 10 SA6Swansea9.6 out of 10

Water suppliers

Dŵr Cymru Welsh Water16 areas

All postcode areas in Wales

Every postcode district we monitor in this region.

CF10 CF11 CF14 CF15 CF23 CF24 CF3 CF30 CF5 SA1 SA2 SA3 SA4 SA5 SA6 SA7

Questions about Wales water

Is tap water safe in Wales?

Based on our analysis of 16 postcode districts in Wales, the average water quality score is 9.5/10, which is safe. Water is supplied by Dŵr Cymru Welsh Water.

Which area has the best water in Wales?

CF30 (Cardiff) has the highest water quality score in Wales at 10.0/10.

Which area has the worst water in Wales?

CF24 (Cardiff) has the lowest water quality score in Wales at 9.3/10. Check the postcode page for details on specific contaminants.

Who supplies water in Wales?

Water in Wales is supplied by Dŵr Cymru Welsh Water.

Data sourced from the Environment Agency Water Quality Archive and water company testing via the Stream Water Data Portal. See our methodology for how scores are calculated. Reviewed by the TapWater.uk research team.