Pipp Brook

• SW of Waterden Wood on the boundary of Crockers Farm smallholding, Coldharbour, Surrey.51.1856°N 0.3535°W / 51.1856; -0.3535[1]
• Mag's Well 51.1974°N 0.3628°W / 51.1974; -0.3628 marking the border of Wotton and Westcott (before the 19th century Westcott was the western hamlet of Dorking) 500m north-east of Leith Hill Tower flowing first north to form one many ravines in the forest that covers all the northern slopes of Leith Hill, Wotton Common, an indented, tapering area with a notable waterfall for the longer stream rising here to the west, the Tillingbourne.

The geological varying depth of greensand top layers caused by erosion towards the underlying clay means that there is no uniform spring line in this part of the Greensand Ridge. The tower is the second highest point in the South-East of England.[2] The Pipp Brook's main tributary, the Milton Brook rises at three close points in farmland on the indented north-east edge of the forest.

During the early nineteenth century the sulphate-rich (chalybeate) waters of the Mag's Well spring were attributed by a countryside travel writer as having aided a person's recovery.[3]

Both the Pipp Brook and the larger River Tillingbourne drain the northern slopes of Leith Hill and the watershed between the two rivers (which runs roughly north-south, marks the boundary between Westcott (which the brook drains entirely) and much larger Wotton.[4][5][note 1]

The Pipp Brook runs almost due east along its Dorking stretch north of much of the town and south of the steep scarp of the North Downs at Ranmore Common before joining the Mole at Pixham.[note 2] The area around the confluence is the subject of occasional riparian (river) flooding as the rate of descent of the Mole decreases significantly and at the Mole Gap becomes or became subterranean, depending on amount of sedimentation.[6]

The Pipp Brook itself has no sewage treatment works, few plains which it drains and as such an extremely narrow and low risk area of riparian flooding.[6] These factors are instead present as to a few parcels of land of east Pixham sometimes considered Dorking by the national media based on a 2010s shorthand by the Environment Agency which has a 'Dorking Flood Area' comprising the sewage works, a handful of properties in Pixham and much of Brockham and Betchworth well upstream along the Mole to the east which are separated by more than a mile from Dorking and are narrowly in its post town.[6][7]