Data from weekly water quality monitoring of the River Frome at East Stoke, Dorset (National Grid Reference SY 867868). The dataset consists of nitrate, soluble reactive phosphorus, dissolved silicon, pH, alkalinity, potassium, sodium, calcium and magnesium concentrations for the entire 44-year monitoring period, with total phosphorus, total dissolved phosphorus, electrical conductivity, water temperature, chloride, sulphate and ammonium concentration data for periods within the monitoring period. Daily average river flow on the day of sampling (extracted from the National River Flow Archive) is included.