The chemistry of surface water and groundwater is subject to constant changes, which result primarily from meteorologic factors (for instance, amounts and intensity of atmospheric precipitation), hydrologic factors (for instance, degree of hydration of the mountain massif and changes in river flows), and geologic-lithologic factors (type of bedrock). The aim of the present study was to examine the hydrologic and chemical regime of surface and groundwater in the Bystra and Sucha Woda mountain catchments. Between December 2013 and December 2016, a total of 77 series of measurements were collected at a rate of twice per month (n = 611 water samples) at 8 gauging sites, which represented both surface waters (streams, ponds) and groundwater (karst springs). The studied area features two very distinct forms of geology. The southern part is a crystalline region, and the northern part is formed of sedimentary rocks. During field studies, the following were measured: water levels and discharge of streams, conductivity, pH, and temperature of water. At the same time, water samples were collected for laboratory analysis, which included total dissolved solids (TDS) and concentration of Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃^–, SO₄^2–, Cl^–, NH₄⁺, PO₄^3–, NO₃^–, Li⁺, Br^– i F^– ions. Geologic structure produces the greatest impact on water chemistry in the Bystra and Sucha Woda catchments. Waters representing the crystalline region were characterized by significantly lower TDS, conductivity, and ion concentrations than waters from the crystalline-sedimentary (karst) region. The average TDS for the crystalline region was 14.3 mg · dm^–3, while for the crystalline-sedimentary region, 81.2 mg · dm^–3. Waters in the crystalline region were characterized by a demonstrably lower pH (average 6.5 pH) than waters in the karst region (average 7.7 pH). The low TDS, conductivity and concentration of main ions were also accompanied by increased discharge during the summer and autumn. In all the examined waters, there was also a marked decrease in the value of these parameters during the spring thaw. In the feeding of streams and karst springs during this time, low-mineral-content meltwaters had their significant share. In spring, there was also the greatest variation in the chemistry of the studied waters. This variability was clearly lower in the Bystre Dolne karst spring than in the Goryczkowe karst string. This was most likely related to a different rate of meltwater inflow in the two karst springs. In the tested waters, the highest TDS, conductivity and concentration of main ions occurred at winter low discharge, which resulted from the predominance of groundwater influx in river discharge. In all the studied waters, a clear decrease in the NO₃ ^– concentration was observed during the summer and autumn months. Most probably, this was associated with increased NO^– uptake by plants during the growing season. In streams draining the crystalline part of the Bystra catchment there was clearly a lower nitrate concentration than in the Bystra stream draining the crystalline-sedimentary (karst) part. The chemistry of Bystra stream water draining the crystalline-sedimentary (karst) part of the catchment was closely dependent on the chemistry of groundwater from the Goryczkowe and Bystre Dolne karst springs.