The paper describes results of monitoring activities of groundwater in a rural area carried out to verify the impact on water quality in an uncontaminated area resulting from the initiation of an atmospheric pollution source. Significant emissions of nitrogen oxides from the pollution source resulted in particular attention to verifying the increase of nitrate concentrations in monitored water. Over 10,000 analytical tests including several chemical parameters were conducted in the full monitoring period. In the paper, a first reading of data, graphical trends and non-parametric statistical analysis are presented. Measured values for nitrates, nitrites, hardness, alkalinity and pH showed poor variability during the entire period. Checked parameters were in the usual ranges of uncontaminated rural areas and comparisons between meaningful values of the periods ante operam and post operam do not show any degradation of water quality following the atmospheric pollution source activity. Nitrites are occasionally found in some spring water due to organic pollution, confirmed by the randomness with which their presence was detected.