| Zone | Definition | Characteristics |
| S1 | Wellhead protection zone | It must prevent damage to the groundwater supply or artificial recharge facilities, as well as prevent pollution in its immediate surroundings |
| S2 | Inner protection zone | It defines an area suitable for preventing pollution (i.e., germs, viruses, and contaminants arising from surface excavation or subsurface works) reaching the groundwater supplies |
| S3 | Outer protection zone | It must provide sufficient space and time for remediation when accidental pollution threatens a groundwater supply |