| Drainage area | Volume in million cubic meters per year | Percentage of water abstracted |
| Lake Victoria | 11,672 | 2.2 |
| Rift valley | 2784 | 1.7 |
| Athi River | 1152 | 11.6 |
| Tana River | 3744 | 15.9 |
| Ewaso Ng’iro | 339 | 12.4 |
| National | 20,291 | 5.3 |