Cannington Brook is formed by a number of headwaters that rise in the Quantock Hills. Two of these rise on Middle Hill and Lydeard Hill which flow for a short distance in a North Easterly direction. The Middle Hill stream is known as Peart Water, at Hawkridge the waters are collected to form the Hawkridge Reservoir. From the reservoir, Peart Water continues through Spaxton and on to a second reservoir, Ashford Reservoir. From Ashford reservoir the stream is now Cannington Brook and just beyond the reservoir further headwaters, which rise in Great Wood on the Quantock Hills, join the flow. These combined waters then flow to the west of Cannington where a small stream from Padnoller joins. It then flows through Cannington before joining the River Parrett.
Hawkridge Reservoir situated in an Area of Outstanding Natural Beauty holds approximately 850 million litres of water and provides water for the town of Bridgwater. It was constructed in the early 1960s.