The lake lies just west of the centre of the city of Stavanger in the Eiganes og Våland borough.

At 0.45 square kilometres (110 acres), it is the third largest lake in the city of Stavanger after Hålandsvatnet and Stora Stokkavatnet.

The Great Fire of Holmen in Stavanger in 1860 showed that the city had a weak water supply.

The city took over several properties along the lake to prevent contamination of drinking water source and it made the surrounding areas into parkland.

After a short time it was realized that Mosvatnet did not have enough capacity to supply the growing city with drinking water in the long term.