| Aquifer | Reserve (Mm3) | Recharge (Mm3/Yr) | TDS (mg/L) | Average depth (m) |
| Dammam | 45,000 | 200 | 2600 - 6000 | 218 |
| Neogene | 130,000 | 360 | 2400 - 4000 | |
| Umm ErRadhuma | 190,000 | 406 | 2000 - 5000 |