timppu: ... Question to Germans: are you really that fanatic for saving water, and for what purpose? Are you afraid you might run out of it?
I can understand saving of hot water better (saving energy, unless you heat it all yourself with solar power or something), but cold water too? Is there a drought in Germany?
I'm asking this too because when I visited Germany as a kid, I recall the toilets were a bit odd already back then, using minimum amount of water.
Note: what the article says about turning off the water while brushing teeth or shampooing your hair, that I don't find that odd. I do that too, even though I don't feel any special need to conserve water. But the other things, like re-using bath water etc...
Let's say it like this: the idea that the environment needs protection is very strong here. So resources should not get wasted. Maybe there was a shortage at some point in history (maybe after the war - I can only speculate) and this event is still imprinted in the cultural memory. Not only water is used much more efficiently than in other rich countries of the world also plastics and other packaging is collected and partly recycled. If you waste resources excessively in general you are a bad guy here. And germans definitely love this super-efficient LED bulbs or super-efficient fridges or other low energy consuming domestic electronic devices (somehow this doesn't hold for cars though). For food this cultural memory also still exists: just be reminded that during 1914-1918 almost a million germans starved to death and after second world war kids got an orange as a christmas present (my parents told me). So I still find it difficult and despicable to throw away food because I bought too much or because I ordered too much. It's something my parents gave to me.
So maybe it is a cultural inherited behavior coming from a time where you had to be super efficient and not wasting any resources.
Or maybe it is just a general cheapskate-ness or if you want to say so: natural austerity. After all a penny saved is a penny got. Water still costs money. Using a water efficient toilet - sure, this is always the better alternative. Sharing still hot bathing water - also saves time. Using water from the kitchen to also water plants - why not. All this are reasonable measures. Still it's not that extreme. Probably only a minority does it all but a majority will at least does some of these things.
It's good from an ecological point of view - after all the ecological footprint of mankind is an often discussed concept nowadays and I'm proud to say that here public opinion was probably a bit ahead of the curve on this important topic. Whenever I travel abroad I'm surprised how popular beverages in cans still can be - here cans lost in favor of bottles during the 1990s mostly.
On the other hand some things are probably outright stupid. You can do overshoot in everything and drive it to the extremes. Collecting all that plastics when then at most are recycled to 40% or less and the rest is burned, doesn't make a lot of sense. One has to keep the balance. But going back to inefficient toilets? Why? I don't see any advantage in this and cannot understand any potential fascination with outdated and inefficient devices.
Some things I don't understand from your question. Are you talking about cold water in baths? I usually do not bathe in cold water.
And about the potential drought in germany. No there is probably not that much chance for it and we could spent more water if we wanted too (which would still cost more money though). Weather extremes have increased lately, so sometimes there is too much water (coming down). So I think this peculiar behavior is expression of a preference of efficient resource usage driven by the desire to save money as well as a generally imprinted cultural awareness that resources (on a global level) are scarce and one needs to use them as efficient as possible and of course there is also some overshooting beyond what is reasonable going on there. Some things will be stupid.
But there are regions that could use efficient water management technologies. Many regions in the US (Midwestern for example) use more water than is refilled by rain every year and consequently the ground water levels are going down. You don't need to be a prophete to predict severe problems coming up. And then there are even more unfavorable regions on earth. I think these can definitely profit from our knowledge for whatever reason we acquired it. So no going back to inefficient toilets for noone - I hope.