| Transmissivity (m2/day) | Designation of T Magnitude | Groundwater Supply Potential |
| >1000 | Very high | Withdrawals of great regional importance |
| 100 - 1000 | High | Withdrawals of lesser regional importance |
| 10 - 100 | Intermediate | Withdrawals for local water supply (small communities, plants etc.) |
| 1- 10 | Low | Smaller withdrawals for local water supply (private consumption) |
| <1 | Very low | Withdrawals for local water supply with limited consumption |