[1] The main source is on the Greensand Ridge at Marley Heights near Haslemere, about 140 metres (460 ft) above sea level.

From here it flows west past Lynchmere, then south to Furnace Pond, where iron cannon were cast during the English Civil War.

Water to power the bellows was provided by an artificial lake covering about 2.5 hectares (6.2 acres) created by a dam on the river.

The mill is now operated at the Weald and Downland Open Air Museum at Singleton, also in West Sussex.

The reasons for the quality being less than good include sewage discharge and runoff of nutrients as a result of agriculture and land management.