Nygardsvatnet is a lake in the municipality of Hol in Buskerud county, Norway. The lake is situated south of the Hallingskarvet mountain range. The lake serves as a reservoir for Usta kraftverk, a hydroelectric plant which was put into operation in 1965. The water level is controlled by a dam at the outlet and a tunnel down to lakes Sløddfjorden and Ustevatn. The Usta kraftverk power plant is owned and operated by E- CO Energi.