Water quality, hardness and compliance in Wales
According to TapWater.uk's analysis, Dŵr Cymru Welsh Water scores 9.5/10 for drinking water quality across 5 monitored postcode districts in 2026. The company reports 99.94% compliance with UK drinking water standards.
Scores sorted by lowest first — worst quality at the top.
Reported compliance with UK drinking water standards.
99.94%
Compliance above 99.9% is the norm across the UK industry, which is why a compliance figure alone says little about how your water actually tastes, scales, or reads locally. The per-district scores and flagged contaminants above are where Dŵr Cymru Welsh Water's supply differs from the national picture.
All postcode districts within Dŵr Cymru Welsh Water's supply network.
Yes. Across 5 monitored postcode districts, Dŵr Cymru Welsh Water's average water quality score is 9.5/10. The lowest-scoring district we monitor is CF10 (9.4/10) and the highest is SA1 (9.6/10).
Hardness readings for Dŵr Cymru Welsh Water's districts are still being collected. Enter your postcode on our hardness checker for the reading in your area.
Dŵr Cymru Welsh Water reported a 99.94% compliance rate against UK drinking water standards. Compliance above 99.9% is the industry norm, which is exactly why we also publish per-district environmental scores and flagged contaminant counts: legal compliance and local water character are different questions.
Dŵr Cymru Welsh Water supplies 3 million customers across Wales. The postcode districts we monitor in its area: CF10, CF11, CF14, SA1, SA2.
Active incidents affecting Dŵr Cymru Welsh Water appear at the top of this page as soon as our monitoring picks them up, alongside the affected postcodes. For supply emergencies always check Dŵr Cymru Welsh Water's own website, which carries the operational updates.