This report describes the results of several stages of archaeological work resulting from plans to construct a new water treatment plant utilising the springhead of the River Jordan at Sutton Poyntz, a village at the foot of the chalk scarp near Weymouth, Dorset. Human activity in the area, since at least Mesolithic times, has focused on the river. Its post-medieval history revolved around its water mills. Evidence for an Early Iron Age settlement and Romano-British activity, including an infant burial were recorded, partly beneath a thick colluvial deposit. A rectangular, stone-founded building has been identified as a 13th-14th century chapel - probably belonging to the Poyntz family estate.