When I made a 10-day car trip around a large part of Iceland some years ago, every single shower I used had that sulfur smell. I guess it's not impossible that

When I made a 10-day car trip around a large part of Iceland some years ago, every single shower I used had that sulfur smell. I guess it's not impossible that the showers I used by sheer coincidence all used the same system. But isn't it also possible that even the water from the heat exchanger system contains some sulfur, in small enough amounts that locals get used to it and don't even smell it anymore, while foreigners still notice the smell. Not only the showers have this smell: it's quite abundant all over the country. Every hot spring smells like that, and Iceland has quite a lot of those. I can easily imagine getting used to it after a few years living there, to the point that you simply don't smell small amounts anymore.