Take a look at the water counter in the picture below:
We found these water counters at the hostel we were lodged in Berlin. I immediately started taking note of how many litres I consumed in each of the showers I took. First one:
I checked in the internet and found references of average consumptions for showers between 80 and 120 litres. The following days I tried to save some water (of course without compromising the cleaning part :-)). The minimum consumption I had was of 34L, the rest in the end were around 42L.
In the process I discussed with Luca whether hotels could incentivize in some ways (other than displaying the counter at our sight) the saving of water by the guests. We thought of possible messages in the way of “the average guest consumes 100L per shower, see if you can use less water! Do it for the planet!”, or whether some discounts / surcharges could be offered / imposed to those consuming less / more water.
However, I checked water prices in France and in Toulouse and it is around 3.3€ per cubic metre (m3). That is, in 5 days, having seen the counter and having tried to minimize water consumption all I saved was about 0.38 m3 or about 1.25€… this is economically meaningless in comparison with the hotel bill.
At those prices, I guess all we could do is trying to save water out of our consciences and not driven by an economic drive (the same level of saving I achieved could mean ~35€ a year per person).