Around 300 people were temporarily evacuated from the municipalities of Monthey and Trois Torrents in the canton of Valais, because of the risk of landslides and high water, state broadcaster RTS reported on its website.
The Vièze River surged beyond its banks on Saturday but levels dropped the following day.
In Saint Gingolphe, a community in the Chablais region of Valais, the Vièze River inundated local streets leaving them strewn with rocks and debris, RTS said.
Two restaurants overlooking Lake Geneva in the community near the French border were heavily damaged.
In Geneva, the high level of the Arve River temporarily forced the closure of several bridges, including the Hans-Wildorf bridge and the Acacias bridge, used by the line 15 tram.
The level of the river, which flows into the Rhône, dropped on Sunday.
But officials warned that the Vessy and Val d’Arve bridges would remain closed on Monday, the Tribune de Genève reported.
“The torrential flooding of the Arve, Saturday, amounts to the most significant flow rate ever registered since 1935 (the date when monitoring equipment was first installed),” François Pasquni, director of the canton of Geneva’s ecology and water service told media.
Several buildings suffered flooding, including the Vernets skating rink, and two science buildings of the University of Geneva, the Tribune said.
Between midnight Friday and midday Sunday Western Switzerland received 70 to 110 percent of the rain it usually receives for the entire month of May, MeteoNews said.
No related deaths or injuries were reported.
Elsewhere in Switzerland, officials were bracing for flooding around Lake Thun, Lake Biel and Lake Neuchâtel, as well as along sections of the Rhone and Aare rivers expected to be hit by fresh rainfall overnight Sunday and early Monday.