When going swimming in a lake, is there any danger in not showering after?
Generally I would shower if there were a lot of other people swimming and the lake was small. And if there was run-off from farms I would not go swimming in that water at all.
Edit: This question is about water that is safe for swimming, does not have cyanobacteria or any other obvious problems with it. It does of course have some poo from water fowl in it and so on.
The lake in question is in the Netherlands and is the result of peat-excavation a long time ago.