Kolufossar

Iceland is a volcanic country so there are hot springs everywhere, but obviously they come with volcanic minerals;-) Most heating is run with such water.
The cold springs are free of the smelly stuff, often the water has percolated through layers of old basalt which works as a purifier.
So heating spring water needs more energy than just using already hot thermal water, but Iceland has plenty of green energy with quite a few geothermal power stations.

That's fascinating about the cold vs hot springs. I never knew that.

In Iceland most tourists quickly learn about the special geology:-)

My brother has been many time to Iceland (he's a geomorphologist), but he never tells me anything (silly brother).