| Bryn Aggregates Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Bryngwyn Hall | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Carmarthen Bay Holiday park | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Castle Dairies Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Celtic Energy Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Celtic Recovery Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Clive Hurt (Plant Hire) Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| CS Grabhire and Groundworks | | | Environmental Violation | 2020 | UK-NRW | £0 |
| D & E Haulage | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Dai Warlow Agri Contractors | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Delta Property Cardiff Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Dragon LNG Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| DW Cummings Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| Dwr Cymru Cyfyngedig | Dwr Cymru Cyfyngedig (Welsh Water) | utilities and power generation | Environmental Violation | 2020 | UK-NRW | £0 |
| E Jenkins & Son | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Easiview Video Services Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Ekocycle Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Enovert North Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Environmental Focus Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Euroforest Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| FIM Services LTD | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Fron Goch Garden Centre | | | Environmental Violation | 2020 | UK-NRW | £0 |
| G D Harries & Sons Ltd. | | | Environmental Violation | 2020 | UK-NRW | £0 |
| G Whittingham & Sons | | | Environmental Violation | 2020 | UK-NRW | £0 |
| GKR Maintenance & Building Co Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Glynneath Golf Club | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Gower Recycling Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Green Skips Environmental Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Gwent Holdings Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Harris Salvage | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Hogan (Construction) Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Hook2sisters Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Howells Fuel oil | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Hydropol Project & Management a.s | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Hydropol Project & Management a.s | | | Environmental Violation | 2020 | UK-NRW | £0 |
| I Wood Renewables Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Ian Williams Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Innogy Renewables UK Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| J.G. Hale Construction Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| JA Insulation Services | | | Environmental Violation | 2020 | UK-NRW | £0 |
| JM Envirofuels Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Jones Bros Ruthin (Civil Engineering) Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
