Water column dissolved silica (SiO2) was analyzed during 2014 in seven freshwater reservoirs in southwestern Virginia (VA), USA. These reservoirs are: Beaverdam Reservoir (Vinton, VA), Carvins Cove Reservoir (Roanoke, VA), Claytor Lake (Pulaski, VA), Falling Creek Reservoir (Vinton, VA), Gatewood Reservoir (Pulaski, VA), Smith Mountain Lake (Bedford, VA), and Spring Hollow Reservoir (Salem, VA). Beaverdam, Carvins Cove, Falling Creek, and Spring Hollow Reservoirs are owned and operated by the Western Virginia Water Authority as primary or secondary drinking water sources for Roanoke, Virginia; Gatewood Reservoir is a drinking water source for the Town of Pulaski, Virginia; and Smith Mountain Lake is jointly treated by Bedford Regional Water Authority and Western Virginia Water Authority as a drinking water source for Franklin County, Virginia. Claytor Lake is utilized for hydroelectric power generation by Appalachian Power Company. The dataset consists of depth profiles of dissolved silica samples generally measured at the deepest site of each reservoir adjacent to the dam and an inflow stream into Falling Creek Reservoir. The water column samples were collected approximately fortnightly from April-June, weekly from June-July and sporadically from July-October at Beaverdam Reservoir; weekly from April-July and fortnightly from July-November at Carvins Cove Reservoir; sporadically from April-August at Claytor Lake; weekly from April-November at Falling Creek Reservoir; fortnightly from April-October at Gatewood Reservoir; fortnightly from May-November at Spring Hollow Reservoir; and fortnightly from May-October at Smith Mountain Lake.