[KellyCriterion]

> hrow water on the rocks?

Depends on the location! Very often, at public locations there is a "saua master" taking care, in smaller locations I have seen people handling this on their own.

And in one location there was a sign: "no private watering due to electrical issues"

[mesrik]

I think I've heard US it's mostly no water at all on stove and Germany I've heard they have had these sauna-masters who come and cast water on stove.

Neither of these are practised anywhere in Finland at least. But there are at least one Finnish swimming bath where they had to limit steam competitions and made a button controlled mechanism to administer water instead of free usage. Not because electrical shock prevention but because bad human behaviour per se.

[euroderf]

The men's sauna at Harjutori in Helsinki has a pullchain (with a handle of wood, natch), by the entrance to the room. When you walk into the men's sauna (which is BIG), you can inquire whether löyly is needed, and affirmative answers dictate a tug or two or three on the chain, which releases bursts of steam.

And anyone on the highest bench really gets cooked.