Nervatnet is a lake that lies in Fauske Municipality in Nordland county, Norway. The 4.8-square-kilometre (1.9 sq mi) lake lies just east of the town of Fauske. The neighboring lake Øvervatnet flows into Nedrevatnet, whose water in turn flows out into the Skjerstad Fjord. The E6 highway and the Nordland Line run along the western edge of this lake.