The paper presents a study on water quality concerning nutrients in relation to the hydrological and meteorological conditions in three agricultural catchments in Latvia. Statistical analysis, i.e., descriptive statistics, Kolmogorov–Smirnov test, Mann-Whitney U test, Spearman’s Rank–Order correlation and cumulative probability function has been used to quantify relationships between variables. Results of the study could be used to evaluate the impact of agricultural intensity on water quality.