This dataset comprises of weekly concentrations of fluoroquinolones in wastewater and receiving waters collected in the Avon river catchment South West UK. The following fluoroquinolones were analysed: (±)-ofloxacin, (±)-ofloxacin-N-oxide, (±)-desmethyl-ofloxacin, (±)-lomefloxacin, (±)-moxifloxacin, S,S-moxifloxacin-N-sulfate, R-(+)-besifloxacin, (±)-prulifloxacin, (±)-ulifloxacin, (±)-flumequine and (±)-nadifloxacin; ciprofloxacin, desethylene-ciprofloxacin, norfloxacin and nalidixic acid. The concentrations of (fluoro)quinolones were measured in receiving treated wastewater from 5 wastewater treatment plants (WWTPs), which serves 1.5 million people accounting for 75% of inhabitants living in the catchment area in the South West of England. NERC Grant NE/N019261/1 Full details about this dataset can be found at https://doi.org/10.5285/f4c79bd3-3ce9-4f4e-ae19-bb4fd2dce7a5