The catchment area of the river is approximately and the average daily flow for the entire catchment is estimated to be . Water from tributaries such as Hillfarrance Brook, Halse Water, Haywards Water, Three Bridges Stream, Sherford Stream and Broughton Brook feed the river but are supplemented by controlled releases from Clatworthy and Luxhay Reservoirs during dry periods. The tributaries flowing into the Tone from the south bring water from the Blackdown Hills.