The aim of the analysis was to compare the physicochemical variables of the quality of shallow groundwater in the peatlands of Eastern Poland in the context of the occurrence of selected herb species with similar habitat requirements: bogbean (Menyanthes trifoliata), small cranberry (Oxycoccus palustris), and purple marshlocks (Comarum palustre). The analysis of the quality variables of the shallow groundwater included the following physicochemical variables: reaction (pH), electrolytic conductivity (EC), dissolved organic carbon (DOC), total nitrogen (Ntot.), ammonium nitrogen (N-NH4), nitrite nitrogen (N-NO2), nitrate nitrogen (N-NO3), total phosphorus (Ptot.), phosphates (P-PO4), sulphates (SO2), sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg). Internal metabolism was shown to influence the hydro-chemical status of peatland water, free of substantial human impact. The variables tested were within the range of the habitat preferences of the herb species and indicated that they have a wide ecological tolerance. However, their identical habitat preferences were not reflected in identical values for the physicochemical variables of the water essential for building populations of these species. The occurrence of these plant species was also shown to be determined by the hydro-chemical characteristics of the habitat, but the characteristics of their occurrence did not indicate the hydro-chemical aspect of the habitat.