| Flachsee | |
|---|---|
| Location | Aargau |
| Lake type | reservoir |
| Primary inflows | Reuss River |
| Primary outflows | Reuss River |
| Basin countries | Switzerland |
| Surface area | 0.72 km² |
| Max. depth | 7 m |
| Surface elevation | 378 m |
Flachsee is an artificial lake on the Reuss River at Rottenschwil, south of Bremgarten in the Aargau region of Switzerland. The reservoir was formed after the construction of the dam in 1975 at Bremgarten-Zufikon. The lake's surface area is 0.72 km².