The paper presents results calculated for radiation exposure of plants (aquatic, aero-aquatic and coastal) growing at man-made and naturally occurring water bodies at the Semipalatinsk Test Site (STS). The peak overall exposure dose rate was 0.078 mGy/day for coastal plants of man-made water bodies that resulted from off-normal situations during underground nuclear tests. As part of the conservative assessment, the peak overall exposure dose rate was 1.3 mGy/day for aquatic plants of man-made water bodies that resulted from excavation blasts. A publication by the International Commission on Radiological Protection says that there is no information on the manifestation of any effects for the dose rate range of 0.01 to 10 mGy/day for these plant species. Based upon findings, exposure doses to plants calculated from the radioecological survey of STS water bodies were found to be well below the threshold level of the ‘dose limit’ from different reported data. The output indicates that nothing threatens (endangers) the ecosystem health of STS water bodies.