List of the interested companies who submitted EOIs for Riyadh-Qassim IWTP Project. A total of 31 companies including 19 Saudi companies expressed their interest in the Project as follows:
| EOI # | Interested Party |
| 1 | Abdul Aziz Al Ajlan Sons Co. for Commercial & Real Estate Investment – Ajlan & Bros |
| 2 | Abengoa Agua S.A. |
| 3 | Abu Dhabi National Energy Company PJSC (TAQA) |
| 4 | Acciona Agua S.A. |
| 5 | Al Fahd Company Trading Industries & Contracting |
| Alghanim International General Trading & Contracting Co. W.L.L | |
| 6 | Al Bawani Water & Power (AWP) |
| 7 | Alkhorayef Water and Power Technologies Company |
| 8 | Al-Rawaf Contracting Company |
| 9 | Al Sharif Group Holding’s |
| SICIM SPA | |
| 10 | ARABIAN BEMCO CONTRACTING CO. |
| 11 | A. Hak Pijpleidingen Saudi Company Limited |
| 12 | China Gezhouba Gruop Co. Ltd (CGGC) |
| 13 | China Harbour Engineering Co. Ltd (CHEC) |
| 14 | Branch of China Petroleum Pipeline Engineering Co. Ltd. |
| 15 | China Railway Construction Corporation (International) Limited |
| 16 | Civil Works Company Ltd. |
|
17 |
El-Seif for Commercial Investments Limited (ESI) |
| Al Qahtani Group of Companies | |
| El Seif Engineering Contracting | |
| El Seif Operations & Maintenance | |
| 18 | Gulf Investment Corporation |
| 19 | Hassan Allam Holding S.A.E |
| 20 | Kindasa Water Services Company (KWS) |
| 21 | Lamar Holding W.L.L |
| 22 | Marubeni Corporation |
| 23 | Mowah Co. (CJSC) |
| 24 | Mutlaq Al-Ghowairi Company (MGC) |
| 25 | Nesma Co. Ltd. |
| 26 | Orascom Construction (OC) |
| 27 | PASSAVANT Energy & Environment GmbH |
|
28 |
Petroleum vision company |
| Saad Ali Al Essa group for trading and contracting | |
| 29 | Powerchina International Group Limited |
| 30 | TECTON Engineering & Construction Saudi Contracting Company |
| 31 | Vision International Investment Company |