Continuous measurements of conductivity, dissolved oxygen, pH, temperature and water level from the Frome Piddle; Pang Lambourn and Tern catchments, recorded between 2002 and 2007. YSI sondes were installed at 16 sites in these catchments to record continuous measurements of conductivity, dissolved oxygen, pH and temperature. Druck pressure transducers were installed at the same sites to measure continuous water level values. The instruments were installed as part of the NERC funded Lowland Catchment Research (LOCAR) Programme to provide comparable baseline river water chemistry data across the LOCAR catchments. Data were collected continuously at 15-minutes intervals for periods of variable length, depending on site.