- Drinking Water 2025 – Summary of the Chief Inspector’s report for drinking water in Wales
- Foreword
- Introduction
- Water supplies and testing
- Compliance with standards
- Learning from compliance failures
- Learning from events
- Consumer contacts
- Asset health
- Water safety planning and risk assessment
- Poly and perfluoroalkyl substances (PFAS)
- Audit programme
- Recommendations
- Enforcement
- Security and Emergency Measures Direction - SEMD
- Network and Information Systems - NIS
- Materials in contact with drinking water (Regulation 31)
- Research publications
- Whistleblowers
- Working with stakeholders
- Annex A – Number of tests carried out by companies
- Annex B – Compliance with standards
- Annex C – Compliance failures and events
Annex C – Compliance failures and events
Top 50 compliance failures in 2025
| Company code | Site name | Parameter name | Inspector assessment | CRI score |
|---|---|---|---|---|
| DWR | Court Farm WTW Final | Coliform bacteria | Covered by Legal Instrument | 1.670 |
| HDC | Llandinam New BPS | Turbidity (WTW) | Unlikely to Recur | 1.212 |
| DWR | Bretton WTW Final | Coliform bacteria | Covered by Legal Instrument | 0.420 |
| DWR | Hereford Central / North | Iron | Covered by Legal Instrument | 0.337 |
| DWR | Holywell / Mold | Iron | Covered by Legal Instrument | 0.323 |
| DWR | Holywell / Mold | Iron | Covered by Legal Instrument | 0.323 |
| DWR | Malpas / Caerleon / Cwmbran | Iron | Covered by Legal Instrument | 0.317 |
| DWR | Malpas / Caerleon / Cwmbran | Manganese | Covered by Legal Instrument | 0.317 |
| DWR | Rhymney / Bargoed | Iron | Covered by Legal Instrument | 0.315 |
| DWR | Cardiff Bay / Rumney | Iron | Covered by Legal Instrument | 0.303 |
| DWR | Pencoed / Bridgend Valleys | Iron | Covered by Legal instrument | 0.294 |
| DWR | Sketty / Gower | Iron | Covered by Legal Instrument | 0.273 |
| DWR | Barry / Sully | Iron | Covered by Legal Instrument | 0.260 |
| DWR | Alaw South WTW Final | Coliform bacteria | Covered by Legal Instrument | 0.210 |
| DWR | Newport West | Iron | Covered by Legal Instrument | 0.185 |
| DWR | Newport West | Iron | Covered by Legal Instrument | 0.185 |
| DWR | Port Talbot / Skewen | Iron | Covered by Legal Instrument | 0.156 |
| DWR | Birchgrove SRV | Coliform bacteria | Unlikely to Recur | 0.125 |
| DWR | Ross-On-Wye | Odour | Covered by Legal Instrument | 0.088 |
| DWR | Ross-On-Wye | Taste | Covered by Legal Instrument | 0.088 |
| DWR | Pengarnddu No3 SRV | Coliform bacteria | Recommendations made | 0.087 |
| DWR | Chepstow / Caldicot | E. coli | Satisfactory investigation, did not identify cause | 0.079 |
| DWR | Abergele / Rhyl | Taste | Unlikely to Recur | 0.057 |
| DWR | Bontgoch | Odour | Recommendations made | 0.053 |
| DWR | Bontgoch | Taste | Recommendations made | 0.053 |
| DWR | Porthmadog SRV | E. coli | Recommendations made | 0.053 |
| DWR | Barry / Sully | Coliform bacteria (zone) | Satisfactory investigation, did not identify cause | 0.043 |
| DWR | Porthmadog SRV | Coliform bacteria | Recommendations made | 0.043 |
| DWR | Newport | Coliform bacteria (zone) | Satisfactory investigation, did not identify cause | 0.041 |
| HDC | Llangollen | Coliform bacteria (zone) | Satisfactory investigation, did not identify cause | 0.040 |
| DWR | North Anglesey | Iron | Unlikely to Recur | 0.037 |
| DWR | Bontgoch | Odour | Suggestions made | 0.035 |
| DWR | Bontgoch | Odour | Suggestions made | 0.035 |
| DWR | Bontgoch | Taste | Suggestions made | 0.035 |
| DWR | Chepstow / Caldicot | Coliform bacteria (zone) | Satisfactory investigation, did not identify cause | 0.032 |
| DWR | Penllain SRV | Coliform bacteria | Covered by Legal Instrument | 0.032 |
| DWR | Pendine | Iron | Covered by Legal Instrument | 0.031 |
| DWR | Pendine | Iron | Covered by Legal Instrument | 0.031 |
| DWR | Rhosymryson SRV | Coliform bacteria | Unlikely to Recur | 0.023 |
| DWR | Hafod SRV | Coliform bacteria | Suggestions made | 0.020 |
| DWR | Fforchneol SRV | Coliform bacteria | Covered by Legal Instrument | 0.017 |
| DWR | Clawydd Newydd Bpt | Coliform bacteria | Covered by Legal Instrument | 0.010 |
| DWR | Monmouth / Trellech | Coliform bacteria (zone) | Satisfactory investigation, did not identify cause | 0.010 |
| DWR | Axton SRV | Coliform bacteria | Covered by Legal Instrument | 0.007 |
| DWR | Woodhouse SRV | Coliform bacteria | Satisfactory investigation, did not identify cause | 0.007 |
| HDC | Hirnant DSR | Coliform bacteria | Recommendations made | 0.007 |
| DWR | New Forest SRV | E. coli | Satisfactory investigation, did not identify cause | 0.007 |
| DWR | Cefn Saeson SRV | Coliform bacteria | Unlikely to Recur | 0.006 |
| DWR | Penwallis SRV | Coliform bacteria | Suggestions made | 0.006 |
| DWR | New Forest SRV | Coliform bacteria | Satisfactory investigation, did not identify cause | 0.006 |
Top 50 events in 2025
| Company code | Event name | Final classification | Inspector assessment | ERI score |
|---|---|---|---|---|
| DWR | Regulation 31 Approval | 3 (Significant) | Prosecution considered | 5,298.682 |
| ALE | Broughton Mains | 3 (Significant) | Recommendations made | 657.000 |
| DWR | Aston Burst | 3 (Significant) | Enforcement-legal instrument | 245.807 |
| DWR | Bryn Cowlyd WTW Loss of Supply | 4 (Serious) | Recommendations made | 164.334 |
| DWR | Cardiff Discolouration | 3 (Significant) | Enforcement-legal instrument | 30.856 |
| DWR | Llanrumney Burst Main | 2 (Minor) | Enforcement-legal instrument | 3.631 |
| DWR | Carmarthen Loss of Supply | 3 (Significant) | Enforcement-legal instrument | 3.026 |
| DWR | Gower/Swansea Discolouration | 3 (Significant) | Suggestions made | 1.570 |
| DWR | Rhyl Discolouration | 2 (Minor) | Suggestions made | 1.564 |
| DWR | Swansea Discolouration | 2 (Minor) | No recommendations or suggestions made | 0.807 |
| DWR | Cardiff Taste and Odour | 3 (Significant) | Recommendations made | 0.788 |
| DWR | St Mellons T&O | 2 (Minor) | No recommendations or suggestions made | 0.549 |
| DWR | Caernarfon Do Not Use | 3 (Significant) | Enforcement-legal instrument | 0.272 |
| DWR | Haverfordwest Boil Water Notice | 3 (Significant) | Recommendations made | 0.127 |
| DWR | Carmarthen Boil Water Advice | 3 (Significant) | Enforcement-legal instrument | 0.119 |
| DWR | Llanrumney Do Not Drink | 3 (Significant) | Enforcement-legal instrument | 0.079 |
| HDC | Market Street Llangollen DND | 3 (Significant) | Recommendations made | 0.055 |
| DWR | Caernarfon Do Not Drink | 3 (Significant) | Recommendations made | 0.048 |
| HDC | Gresford Lead DND | 2 (Minor) | No recommendations or suggestions made | 0.044 |
| DWR | Moreton-on-Lugg Do Not Drink | 3 (Significant) | Suggestions made | 0.030 |
| DWR | Plas Talgarth SRV E.coli Detection | 2 (Minor) | No recommendations or suggestions made | 0.017 |
| DWR | Llanelli Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.011 |
| HDC | Wrexham Lead Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.011 |
| HDC | Saltney Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.003 |
| DWR | Holywell Lead DND | 2 (Minor) | No recommendations or suggestions made | 0.002 |
| HDC | Llwyn Onn Gravity DND | 2 (Minor) | No recommendations or suggestions made | 0.002 |
| DWR | Llangoedmor Boil Water Notice | 2 (Minor) | No recommendations or suggestions made | 0.001 |
| DWR | Walwyns Castle Do Not Drink | 2 (Minor) | Enforcement-legal instrument | 0.001 |
| DWR | Abercarn Boil Water Notice | 2 (Minor) | Enforcement-legal instrument | 0.001 |
| DWR | Porth Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.001 |
| DWR | Llandudno Lead Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | New Forest SRV E.coli detection | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Llanfwrog (Lead) Do Not Drink | 2 (Minor) | Suggestions made | 0.000 |
| DWR | Narberth Do Not Drink | 1 (Not Significant) | No recommendations or suggestions made | 0.000 |
| DWR | Kington Do Not Drink | 1 (Not Significant) | No recommendations or suggestions made | 0.000 |
| DWR | Talgarth (Lead) Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Pontardawe Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Whitland Do Not drink | 1 (Not Significant) | No recommendations or suggestions made | 0.000 |
| DWR | Dinas Mawddwy Boil Water Notice | 1 (Not Significant) | No recommendations or suggestions made | 0.000 |
| DWR | Caerphilly (Lead) Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Dyserth, Rhyl Do Not drink (Lead) | 1 (Not Significant) | No recommendations or suggestions made | 0.000 |
| DWR | Ebbw Vale Do Not Drink | 1 (Not Significant) | Suggestions made | 0.000 |
| DWR | Porthmadog SRV E.coli detection | 3 (Significant) | No recommendations or suggestions made | 0.000 |
| DWR | Abergavenny Fuel DND | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Rhyl Lead DND | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Blackwood Lead Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Cowbridge DND | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Cardiff Do Not Drink | 1 (Not Significant) | No recommendations or suggestions made | 0.000 |
| DWR | Llandudno Do Not Drink (Lead) | 2 (Minor) | No recommendations or suggestions made | 0.000 |
| DWR | Llandudno Do Not Drink | 2 (Minor) | No recommendations or suggestions made | 0.000 |