Bradworthy S.T.W. N.G.R. SS 329 135, is a small treatment works with a numeric consent utilising a biological filter system, the final effluent discharges into the River Waldon. However heavy rainfall may cause untreated effluent from the storm settlement tanks to discharge into the river via a screening process. The Devon Area Investigation Team were requested by the Devon Area Water Quality Team to investigate how frequently the storm sewer overflow operated. The data was to be collected and passed on to the Devon Area Water Quality Officer responsible for the Bradworthy catchment.