All of the run-off from the fell finds its way ultimately to Crummock Water, the Derwent-Cocker watershed ignoring Wandope in favour of the onward connection from Crag Hill to Ard Crags. Sail Beck carries the water from the south and east, running out from between Knott Rigg and Whiteless Pike into Buttermere village. Addacomb Beck and Third Gill are the tributaries which mark the northern and southern boundaries of Wandope on this flank. To the north and west of the fell is Rannerdale Beck, disgorging its flow direct into the centre section of the lake.