The name “Bilbrook” may have come from the word “Billars”(a watercress-like plant which grows in water), and the stream which flows through Bilbrook, the Moat “Brook”. It is thought that billars grew in the Moatbrook for centuries. The Moatbrook, which flows into the River Penk at Pendeford, forms much of the northern boundary of the Civil Parish of Bilbrook. The River Penk flows into the River Sow, which is a tributary of the River Trent, so its waters flow into the North Sea via the Humber Estuary.