## 3 Results
### Hydrometeorological Conditions in the Catchment of the River Swierszcz
#### 3.2.1 Analysis of Selected Microbiological Indicators  
Table 3 compares the descriptive statistics of the microbiological parameters of rainwater with those of flowing water and groundwater. The distributions of the obtained values of the microbiological test for the analysed types of water are presented in box plots (Figure 8), together with information on the statistical differences. Statistically significant differences were found in the distribution of the total microbial counts at 36 \({}^{\circ}\)C (Kruskal-Wallis H = 12.38, \(p\) = 0.006). The rainwater collected at points P1 and P2 contained significantly higher bacterial counts than water collected from deep wells, but no significant differences were found in relation to the flowing waters at P3 (Figure 8a). The rainwater sampled at P1 and P2 showed 40% and 20% compliance with drinking water standards, respectively. The average total microbial count at 36 \({}^{\circ}\)C in rainwater (P1 and P2) was more than 8 times higher than the limit value stipulated for drinking water (Tables 1-3) [36]. This contamination of rainwater was likely to have been influenced by bird droppings found on the surfaces of the roofs from which rainwater was harvested. A much lower average total microbial count at 36 \({}^{\circ}\)C was determined for water from the River Swierszcz, which, however, was also more than 3 times higher than the drinking water limit (Tables 2 and 3) [36]. In the case of rainwater sampled at point P1 and river water (P3), the variation in total bacterial counts at 36 \({}^{\circ}\)C (Table 3) was extremely high. The only type of water in which the drinking water limit was not exceeded was the deep well water (P4-P7) [36]. However, even here, small numbers of microorganisms were present at 36 \({}^{\circ}\)C (Table 3). Statistically significant differences were found in the distribution of the total microbial counts at 22 \({}^{\circ}\)C (Kruskal-Wallis H = 10.67, \(p\) = 0.014). The rainwater collected at points P1 and P2 contained significantly more bacteria than the water sampled from deep wells, but no significant differences were found relative to the flowing water at P3 (Figure 8b). Statistically significant differences were observed in the distribution of coliform counts (Kruskal-Wallis H = 14.33, \(p\) = 0.003). The rainwater collected at points P1 and P2 did not contain significantly higher numbers of bacteria compared with the well water. However, there were fewer bacteria in the rainwater sampled at point P1 than in the water collected from the River Swierszcz (P3) (Figure 8c). Water from the deep wells (P4-P7) was the only type that did not contain coliform bacteria. Relationships similar to those for coliform counts were found for _Escherichia coli_ (Kruskal-Wallis H = 19.06, \(p\) \(<\) 0.001) (Figure 8d). Again, the deep waters (P4-P7) were the only ones to comply with the drinking water standard [36]. In rainwater collected at sampling point P1, _Escherichia coli_ was found only once, namely, in July 2021, and its count exceeded the drinking water limit (Table 3). Compliance with drinking water standards for rainwater was 90% and 40% for P1 and P2, respectively. The largest counts of _Escherichia coli_ were found in water coming from the River Swierszcz. The types of water we tested differed statistically in the distribution of intestinal enterococci counts (Kruskal-Wallis H = 9.46, \(p\) = 0.024). Significantly higher numbers of these bacteria were found in the rainwater collected at point P2 than in the water collected from the deep wells (P4-P7). By contrast, there were no significant differences in the number of intestinal enterococci in water sampled at points P1 and P3 (Figure 8e). Compliance with drinking water standards for rainwater was 40% and 10% for P1 and P2, respectively. Samples of deep well water (P4-P7) were the only ones in which the drinking water standard stipulated for intestinal enterococci was not exceeded [36].