| Flassavatnet | |
| Pushpin Map: | Rogaland#Norway |
| Pushpin Label Position: | bottom |
| Pushpin Map Caption: | Location of the lake |
| Location: | Gjesdal and Sandnes, Rogaland |
| Coords: | 58.7892°N 5.8688°W |
| Basin Countries: | Norway |
| Area: | 0.9243km2 |
| Islands: | 1 island (Holmen) and several islets |
| Reference: | NVE |
Flassavatnet is a lake in Rogaland county, Norway.[1] The lake lies on the border of the municipalities of Gjesdal and Sandnes. The 0.9243km2 lake sits about north of the large village of Ålgård, not far north of the lakes Edlandsvatnet and Limavatnet. The lake is a reservoir with a small dam on the southern edge of the lake. The water level is kept at about above sea level. The reservoir holds about 900000m2.[2]