This dataset contains surface water and groundwater chemistry data of 111 samples - 41 surface waters, 63 groundwater, and 7 groundwater duplicates - collected at the UK Geoenergy Observatory (UKGEOS) in Glasgow, between 20 September 2022 and 12 January 2024 by the British Geological Survey (BGS), as part of the monitoring programme at the Glasgow research facility (https://www.ukgeos.ac.uk/glasgow-observatory). Samples are from 6 surface water sites, 5 mine water boreholes, and 5 environmental monitoring boreholes and were analysed at BGS and other laboratories. It includes the following parameters: field measurements of redox potential (ORP), pH, dissolved oxygen, electrical conductivity, alkalinity and water temperature, as well as chemical analyses of major, minor, and trace elements, non-purgeable organic carbon (NPOC), polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), oxygen and deuterium isotopes (δ2H and δ18O), carbon isotopes in dissolved inorganic carbon (DIC) (δ13CDIC), and – limited to the groundwater samples – ammonium (NH4), reduced iron, dissolved sulphide, dissolved gases radon, methane, ethane and carbon dioxide (Rn, CH4, C2H6, CO2) and volatile organic compounds (VOC). The dataset consists of two excel files: GroundWaterChemData3 and SurfaceWaterChemData4, with an accompanying report by Palumbo-Roe et al. (2025).