If you remove a single player game installation with the Delete Local Content option from the Steam Libary, in general will save files be deleted or retained?
In general, the Delete Local Content option will remove everything from a game’s folder located in the
steamapps directory except for the save files – they will be kept. There are a few exceptions to this, however, so take care.
In cases where anything is kept in an external directory, that will also not be removed. Many games nowadays have Steam Cloud enabled, which syncs your savefiles with an online database. This means that your save files will not only be kept, but synchronized with any computer you might want to play them on.
For Source games in particular, additional data will often be kept in more general Steam folders, too, and will then not be deleted.
Check if the game you want to delete has Steam Cloud enabled, and if not, check if the save data is kept outside of the game’s
steamapps folder. If none of these are applicable, there is a very small risk that your save data will be deleted – this varies from game to game, though.