The annual average concentration is the simplest and most widely used state indicator for both nitrates and pesticides. The threshold values for the drinking water and groundwater are 50 mg NO3/L for nitrate, 0.1µg/L for a single pesticide, and 0.5 µg/L for the total pesticides (Table 6.2). The Drinking water Directive and Groundwater Directive set these limits.
Validity and robustness of the annual average concentration strongly depend on the quality and quantity of the monitoring data. Furthermore, this indicator does not reflect the temporal and spatial variability of the nitrate and pesticide in the water.
Table 6.2: Summary of state indicators and their threshold values and limits for water quality and regulatory compliances
| Main domain | Indicators | Contaminants | Threshold/ limit | Unit |
| Water quality | Annual average concentrations | NO3 | 50 | mg/L |
| Individual pesticide | 0.1 | µg/L | ||
| Sum of all pesticides | 0.5 | µg/L | ||
| Trend | NO3 | - | upward, downward, no significant | |
| Regulatory compliance | Frequency of exceedance quality standard | NO3 | - | % |
| Individual pesticide | - | % | ||
| Frequency of findings quality standard | Individual pesticide | Detection limit | % | |
| Maximal concentrations | NO3 | 50 | mg/L | |
| Maximal concentrations | Individual pesticide | - | µg/L | |
| Sum of all pesticides | - | µg/L | ||
| All pesticides | - | - | ||
| Number of substances | - | - |