| Water type | Code |
| Groundwater observation well | GWO |
| Groundwater production well | GWP |
| Groundwater infiltration well | GWI |
| Surface water (river, spring, etc.) | SW |
| Precipitation (bulk) | PB |
| Precipitation (dry deposition only) | PD |
| Precipitation (wet deposition only) | PW |
| Throughfall | TF |
| Stem flow | SF |
| Litter leachate | LL |
| Sea water | SEA |
| Lake water | LK |
| Soil core water | CW |
| Soil moisture | SM |
| Solid phase (e.g. soil analysis) | SP |
| Laboratory experiment | LAB |