The River Sheppey has its source in a group of springs west of the village of Doulting, near Shepton Mallet in Somerset, England.

At Coxley it is joined by the Keward Brook which carries the water from the springs in Wells which fill the moat of the Bishop's Palace.

[1] The water quality is generally good; however, there have been some discharges from sewage treatment works in the area that can contribute to nutrient levels in rivers.

Signs of nutrient enrichment are noticeable at times of low flow and the ecology of the Sheppey is adversely affected in its upper reaches.

[6] There may have been more than thirty mills powered by the river and its tributaries in the area of Shepton Mallet, Bowlish and Darshill, although fewer than this number of sites have been positively identified.