| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| ANNIVERSARY TRADING LIMITED | 14136842 | 27/05/2022 | Bronze |
| CASTLE VIEW ENTERPRISE ACADEMY | 06268570 | 06/07/2012 | Silver |
| CENTRICA PLC | 03033654 | 01/01/2020 | Silver |
| CKI UK CO 5 LIMITED | 07509455 | 18/01/2012 | Silver |
| CKI UK CO 6 LIMITED | 07509449 | 18/01/2012 | Bronze |
| ESSEX AND SUFFOLK WATER LIMITED | 02635436 | 23/04/2010 | Bronze |
| GREAT BRITISH RAILWAYS TRANSITION TEAM LIMITED | 14066335 | 01/09/2022 | Amber |
| KIELDER WATER & FOREST PARK DEVELOPMENT TRUST | 07424020 | 29/10/2010 | Bronze |
| NORTHUMBRIAN HOLDINGS LIMITED | 02366698 | 23/04/2010 | Not Trading |
| NORTHUMBRIAN OVERSEAS INVESTMENTS LIMITED | 02820167 | 23/04/2010 | Not Trading |
| NORTHUMBRIAN SERVICES LIMITED | 03114615 | 23/04/2010 | Silver |
| NORTHUMBRIAN WATER COMPANY 1 LIMITED | SC782917 | 19/09/2023 | Bronze |
| NORTHUMBRIAN WATER COMPANY 2 LIMITED | SC782918 | 19/09/2023 | Bronze |
| NORTHUMBRIAN WATER COMPANY 3 LIMITED | SC782919 | 19/09/2023 | Bronze |
| NORTHUMBRIAN WATER FINANCE PLC | 04326507 | 23/04/2010 | Silver |
| NORTHUMBRIAN WATER GROUP LIMITED | 04760441 | 01/03/2010 | Amber |
| NORTHUMBRIAN WATER LIMITED | 02366703 | 01/03/2010 | Amber |
| NWG COMMERCIAL SOLUTIONS LIMITED | 10028815 | 26/02/2016 | Bronze |
| UK WATER (2011) LIMITED | 07509453 | 18/01/2012 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|